Category: Interview Questions

Q1. How To Check The Cluster (one Node) Status?

$ crsctl check crs

CRS-4638:
Oracle High Availability Services is online.

CRS-4537:
Cluster Ready Services is online.

CRS-4529:
Cluster Synchronization Services is online.

CRS-4533:
Event Manager is online.

Q2. List Key Benefits Of Asm?

• Stripes files rather than logical volumes.
• Provides redundancy on a file basis.
• Enables online disk reconfiguration and dynamic rebalancing.
• Reduces the time significantly to resynchronize a trient failure by tracking changes while disk is offline.
• Provides adjustable rebalancing speed.
• Is cluster-aware.
• Supports reading from mirrored copy instead of primary copy for extended clusters.
• Is automatically installed as part of the Grid Infrastructure.

Q3. Can I Stop All Nodes In One Command? Meaning That Stopping Whole Cluster?

In 10g its not possible, where in 11g it is possible

[root@pic1]# crsctl start cluster -all

[root@pic2]# crsctl stop cluster –all

Q4. How To Find Location Of Ocr?

• cat /etc/oracle/ocr.loc

ocrconfig local=+DATA

local_only=FALSE

• #OCRCHECK (also about OCR integrity)

Q5. What Are Oracle Cluster Components?

• Cluster Interconnect (HAIP)
• Shared Storage (OCR/Voting Disk)
• Cluster ware software

Q6. How To Control Oracle Cluster Ware?

To start or stop Oracle Cluster ware on a specific node:

• # crsctl stop crs
• # crsctl start crs

To enable or disable Oracle Cluster ware on a specific node:

• # crsctl enable crs
• # crsctl disable crs

Q7. Crs Is Not Starting Automatically After A Node Reboot, What You Do To Make It Happen?

crsctl enable crs (as root)

to disable

crsctl disable crs (as root)

Q8. Can You Add Voting Disk Online? Do You Need Voting Disk Backup?

Yes, as per documentation, if you have multiple voting disk you can add online, but if you have only one voting disk, by that cluster will be down as its lost you just need to start crs in exclusive mode and add the vote disk using

crsctl add vote disk

Q9. What Is The Major Difference Between 10g And 11g Rac?

Well, there is not much difference between 10g and 11gR (1) RAC.

But there is a significant difference in 11gR2.

Prior to 11gR1 (10g) RAC, the following were managed by Oracle CRS:

• Databases
• Instances
• Applications
• Node Monitoring
• Event Services
• High Availability

From 11gR2 (onwards) it’s completed HA stack managing and providing the following resources as like the other cluster software like VCS etc.

• Databases
• Instances
• Applications
• Cluster Management
• Node Management
• Event Services
• High Availability
• Network Management (provides DNS/GNS/MDNSD services on behalf of other traditional services) and SCAN – Single Access Client Naming method, HAIP.
• Storage Management (with help of ASM and other new ACFS filesystem).
• Time synchronization (rather depending upon traditional NTP).
• Removed OS dependent hang checker etc, manages with own additional monitor process.

Q10. How To Check The Cluster (all Nodes) Status?

To check the viability of Cluster Synchronization Services (CSS) across nodes:

$ crsctl check cluster

CRS-4537:
Cluster Ready Services is online.

CRS-4529:
Cluster Synchronization Services is online.

CRS-4533:
Event Manager is online.

Q11. Managing Or Modifying Scan In Oracle Rac?

To add a SCAN VIP resource:

• $ srvctl add scan -n cluster01-scan

To remove Cluster ware resources from SCAN VIPs:

• $ srvctl remove scan [-f]

To add a SCAN listener resource:

• $ srvctl add scan listener
• $ srvctl add scan listener -p 1521

To remove Cluster ware resources from all SCAN listeners:

• $ srvctl remove scan listener [-f]

Q12. What Is Cluster Ware?

Software that provides various interfaces and services for a cluster. Typically, this includes capabilities that:

• Allow the cluster to be managed as a whole.
• Protect the integrity of the cluster.
• Maintain a registry of resources across the cluster.
• Deal with changes to the cluster.
• Provide a common view of resources.

Q13. What Are Oracle Kernel Components (nothing But How Does Oracle Rac Database Differs Than Normal Single Instance Database In Terms Of Binaries And Process)?

Basically Oracle kernel need to switched on with RAC On option when you convert to RAC, that is the difference as it facilitates few RAC bg process like LMON, LCK, LMD, LMS etc.

To turn on RAC:

• # link the oracle libraries
• $ cd $ORACLE_HOME/rdbms/lib
• $ make -f ins_rdbms.mk rac_on
• # rebuild oracle
• $ cd $ORACLE_HOME/bin
• $ relink oracle

Oracle RAC is composed of two or more database instances. They are composed of Memory structures and background processes same as the single instance database. Oracle RAC instances use two processes GES(Global Enqueue Service), GCS(Global Cache Service) that enable cache fusion.

Oracle RAC instances are composed of following background processes:

• ACMS—
  Atomic Controlfile to Memory Service (ACMS)
• GTX0-j—
  Global Traction Process
• LMON—
  Global Enqueue Service Monitor
• LMD—
  Global Enqueue Service Daemon
• LMS—
  Global Cache Service Process
• LCK0—
  Instance Enqueue Process
• RMSn—
  Oracle RAC Management Processes (RMSn)
• RSMN—
  Remote Slave Monitor

Q14. How To Change Cluster Interconnect In Rac?

On a single node in the cluster, add the new global interface specification:

• $ oifcfg setif -global eth2/192.0.2.0:cluster_interconnect

Verify the changes with oifcfg getif and then stop Cluster ware on all nodes by running the following command as root on each node:

• # oifcfg getif
• # crsctl stop crs

Assign the network address to the new network adapters on all nodes using ifconfig:

• #ifconfig eth2 192.0.2.15 netmask 255.255.255.0 broadcast 192.0.2.255

Remove the former adapter/subnet specification and restart Cluster ware:

• $ oifcfgdelif -global eth1/192.168.1.0
• # crsctl start crs

Q15. What Is Olr? Which Of The Following Statements Regarding The Oracle Local Registry (olr) Is True?

1. Each cluster node has a local registry for node-specific resources.
2. The OLR should be manually created after installing Grid Infrastructure on each node in the cluster.
3. One of its functions is to facilitate Cluster ware startup in situations where the ASM stores the OCR and voting disks.
4. You can check the status of the OLR using ocrcheck.

Q16. What Is The Difference Between Crsctl And Srvctl?

Crsctl manages cluster ware-related operations:

• Starting and stopping Oracle Cluster ware.
• Enabling and disabling Oracle Cluster ware daemons.
• Registering cluster resources.

Srvctl manages Oracle resource–related operations:

• Starting and stopping database instances and services.
• Also from 11gR2 manages the cluster resources like network, vip, disks etc.

Q17. What Is Asm Striping?

ASM can use variable size data extents to support larger files, reduce memory requirements, and improve performance.

1. Each data extent resides on an individual disk.
2. Data extents consist of one or more allocation units.

The data extent size is:

• Equal to AU for the first 20,000 extents (0–19999)
• Equal to 4 × AU for the next 20,000 extents (20000–39999)
• Equal to 16 × AU for extents above 40,000

ASM stripes files using extents with a coarse method for load balancing or a fine method to reduce latency.

• Coarse-grained striping is always equal to the effective AU size.
• Fine-grained striping is always equal to 128 KB.

Q18. What Is Scan Listener?

A scan listener is something that additional to node listener which listens the incoming db connection requests from the client which got through the scan IP, it got endpoints configured to node listener where it routes the db connection requests to particular node listener.

Q19. What Is Gns?

Grid Naming service is alternative service to DNS , which will act as a sub domain in your DNS but managed by Oracle, with GNS the connection is routed to the cluster IP and manages internally.

Q20. How To Check The Node Connectivity In Oracle Grid Infrastructure?

$ cluvfy comp nodecon -n all –verbose

Q21. How Many Asm Disk Groups Can Be Created Under One Asm Instance?

ASM imposes the following limits:

• 63 disk groups in a storage system
• 10,000 ASM disks in a storage system
• Two-terabyte maximum storage for each ASM disk (non-Exadata)
• Four-petabyte maximum storage for each ASM disk (Exadata)
• 40-exabyte maximum storage for each storage system
• 1 million files for each disk group

ASM file size limits (database limit is 128 TB):

1. External redundancy maximum file size is 140 PB.
2. Normal redundancy maximum file size is 42 PB.
3. High redundancy maximum file size is 15 PB.

Q22. What Is Node Listener?

In 11gr2 the listeners will run from Grid Infrastructure software home

• The node listener is a process that helps establish network connections from ASM clients to the ASM instance.
• Runs by default from the Grid $ORACLE_HOME/bin directory.
• Listens on port 1521 by default.
• Is the same as a database instance listener.
• Is capable of listening for all database instances on the same machine in addition to the ASM instance.
• Can run concurrently with separate database listeners or be replaced by a separate database listener.
• Is named tnslsnr on the Linux platform.

Q23. What Is Runfixup.sh Script In Oracle Cluster Ware 11g Release 2 Installation?

With Oracle Cluster ware 11g release 2, Oracle Universal Installer (OUI) detects when the minimum requirements for an installation are not met, and creates shell scripts, called fixup scripts, to finish incomplete system configuration steps. If OUI detects an incomplete task, then it generates fixup scripts (runfixup.sh). You can run the fixup script after you click the Fix and Check Again Button.

The Fixup script does the following:

If necessary sets kernel parameters to values required for successful installation, including:

• Shared memory parameters.
• Open file descriptor and UDP send/receive parameters.

Sets permissions on the Oracle Inventory (central inventory) directory. Reconfigures primary and secondary group memberships for the installation owner, if necessary, for the Oracle Inventory directory and the operating system privileges groups.

• Sets shell limits if necessary to required values.

Q24. What Are Oracle Rac Components?

VIP, Node apps etc.

Q25. How To Stop Whole Cluster With Single Command?

crsctl stop cluster (possible only from 11gr2), please note crsctl commands becomes global now, if you do not specify node specifically the command executed globally

for example:

• crsctl stop crs (stops in all crs resource in all nodes).
• crsctl stop crs –n

Q26. You Have Lost Ocr Disk, What Is Your Next Step?

The cluster stack will be down due to the fact that cssd is unable to maintain the integrity, this is true in 10g, from 11gR2 onwards, the crsd stack will be down, the house still up and running. You can add the OCR back by restoring the automatic backup or import the manual backup.

1. 1. How Does The Telecom Environment Contribute To Achieving Business Objectives?

   Measuring, optimizing and ultimately reducing telecom costs are a primary business objective for many organizations. Data extracted from a TEM system can provide insight into potential areas for optimization, such as identifying unused mobile devices that can be disconnected and/or fixed lines that are underutilized or not used at all. These discoveries provide significant savings back to the organization and the cost savings can be allocated to other technologies that will help propel the business toward achieving its corporate goals.

2. 2. How Do Analytics Help Drive Efficiency?

   Telecom management isn’t just about cost savings anymore; it includes optimizing efficiency of the entire telecom environment through use of Key Performance Indicators (KPIs). These KPIs will help you identify ineffective processes, oversights and bottle necks that are not addressed in standard cost savings data. Armed with accurate feedback on your telecom environment and its processes as a whole, your organization can hone in on creating and/or restructuring processes to be more streamlined and efficient.

Python Interview Questions

3. 3. How Do Telecom Services Affect Customer Retention Objectives?

   Increasing customer retention is a business objective for every organization. Analytics that can be gleaned from IVR systems may show significant customer abandonment for support calls. Organizations can use the information to redesign the IVR for a more fluid, easy-to-understand support experience and improve customer satisfaction – and ultimately retention.

4. 4. How Does Vendor Sla Performance Affect Service Cost?

   Data reveals critical data that informs business decision makers on whether contractual agreements are being met or not. It addresses several key areas of influence like mean repair time, quality of service and if you’re spend is within original budget and contractual agreement.

Python Tutorial

5. 5. What Is The Total Cost Of Ownership For Every Service Type?

   If you’re currently using a vendor, your data is going to provide a breakout of services you have purchased. It includes equipment, carrier, and data costs and envelopes utilization of FTEs. This visibility allows you to manage spend per service component and manipulate costs as needed. An example of this would be an upgrade to equipment costs while lowering data costs or the decision to use bots in place of FTEs.

Android

6. 6. How Does Service Utilization Affect Communications Costs Per Transaction?

   Data analytics identify service usage times as well as idle time in which service goes unused, hence driving communications costs up. Organizations are then able to hone in on optimizing utilization in order to drive effect utilization costs.

   If communications are used to sell service (as in the case of a call center), the technology that is used to conduct communications needs to be optimized to ensure an effective and efficient transaction. If the technology used speeds up the transaction, then the utilization per transaction goes down and creates efficiency against the sale.

7. 7. How Does Technology Innovation Create Competitive Business Advantage?

   Innovation can have a significant influence on a business’s competitive advantage in the marketplace.

   For example:
   data and analytics from a new mobile application released by a retail organization can provide insight into which products are being viewed and purchased the most, resulting in improved product placement in the store to attract more customers.

Android Tutorial
Telecommunication Project Management

8. 8. How Does The Break/fix Help Ticket Resolution Time Affect Service Performance?

   Data analytics simplified vendor management as it grants the evidence that your internal users are or are not getting the support they need. It allows you to see if your vendors are available, reliable, and responsive.  You can easily check meantime to repair on help desk tickets and identify if vendors are meeting contractual terms; arming you with both the info you need to request improved service and/or use as a bargaining tool for negotiations.

9. 9. What Is The Business Value Of Process Efficiency?

   Improvements in process efficiency can be directly correlated with driving real business value.

   For example:
   data extracted from an organization’s financial systems can uncover a significant amount of late payment fees and being paid for telecom invoices. Improvements in invoice processing workflow can reduce the time it takes to process invoices resulting in the elimination of late payment fees.

Tele Sales

10. 10. Do Your Organization’s Mobile Solutions Provide The Support And Security It Needs?

    Data analytics will map what apps your organization is using, how much data its pulling and reveal the need for additional security measures. This enables organizations to develop more effective corporate policies that support Mobile Device Management (MDM) and what kinds of authentication are required.

Telecom Billing Tutorial

1. 1. 1. What Is Basic Teradata Query Language?

      1. It allows us to write SQL statements along with BTEQ commands. We can use BTEQ for importing, exporting and reporting purposes.
      2. The commands start with a (.) dot and can be terminated by using (;), it is not mandatory to use (;).
      3. BTEQ will assume any thing written with out a dot as a SQL statement and requires a (;) to terminate it.

 

1. 1. 2. What Is The Difference Between Fastload And Multiload?

      FastLoad uses multiple sessions to quickly load large amount of data on empty table. MultiLoad is used for high-volume maintenance on tables and views. It works with non-empty tables also. Maximum 5 tables can be used in MultiLoad.

 

Microstrategy Interview Questions

1. 1. 3. Which Is Faster Fastload Or Multiload?

      FastLoad.

 

 

1. 1. 4. Difference Between Inner Join And Outer Join?

      An inner join gets data from both tables where the specified data exists in both tables. An outer join gets data from the source table at all times, and returns data from the outer joined table ONLY if it matches the criteria.

 

Microstrategy Tutorial

1. 1. 5. What Is Multi Insert?

      Inserting data records into the table using multiple insert statements. Putting a semi colon in front of the key word INSERT in the next statement rather than terminating the first statement with a semi colon achieves it.

      Insert into Sales “select * from customer”;
      Insert into Loan “select * from customer”;

 

Informatica Interview Questions

1. 1. 6. Is Multi Insert Ansi Standard?

      No.

 

 

1. 1. 7. How Do You Create A Table With An Existing Structure Of Another Table With Data And With No Data?

      Create table Customerdummy as Customer with data / with no data;

 

Informatica Tutorial
MySQL Interview Questions

1. 1. 8. What Is The Opening Step In Basic Teradata Query Script?

      .Logon tdipid/username, password.

 

 

1. 1. 9. Can You Fastexport A Field, Which Is Primary Key By Putting Equality On That Key?

      No.

 

Oracle 11g Interview Questions

1. 1. 10. Did You Write Stored Procedures In Teradata?

      No, because they become a single amp operation and my company didn’t encourage that.

 

MySQL Tutorial

1. 1. 11. What Is The Use Of Having Index’s On Table?

      For faster record search.

 

Hadoop Interview Questions

1. 1. 12. Is It Necessary To Add? Quit Statement After A Bteq Query When I Am Calling It In A Unix Environment?

      Not necessary but it is good to add a QUIT statement after a query.

 

 

Microstrategy Interview Questions

1. 1. 13. There Is A Column With Date In It. If I Want To Get Just Month How It Can Be Done? Can I Use Sub String?

      Sub string is used with char fields. So it cannot be used. To extract month from a date column, ex select extract (month from ). Same thing for year or day. Or hour or minutes if it’s a time stamp (select extract (minute from column name).

 

Oracle 11g Tutorial

1. 1. 14. What’s The Syntax Of Sub String?

      SUBSTRING (string_expression, n1 [n2]).

 

 

1. 1. 15. While Creating Table My Dba Has Fallback Or No Fallback In His Ddl.
      What Is That?

      FALLBACK requests that a second copy of each row inserted into a table be stored on another AMP in the same cluster. This is done when AMP goes down or disk fails.

 

TeraData DBA Interview Questions

1. 1. 16. My Table Got Locked During Mload Due To A Failed Job. What Do I Do To Perform Other Operations On It?

      Using RELEASE MLOAD. It removes access locks from the target tables in Teradata. It must be entered from BTEQ and not from MultiLoad. To proceed, you can do RELEASE MLOAD

      .

 

 

Hadoop Tutorial

1. 1. 17. How To Find Duplicates In A Table?

      Group by those fields and select id, count(*) from table group by id having count (*) > 1.

 

MYSQL DBA Interview Questions

1. 1. 18. How Do You Verify A Complicated Sql?

      I use explain statement to check if the query is doing what I wanted it to do.

 

 

Informatica Interview Questions

1. 1. 19. How Many Tables Can You Join In V2r5?

      Up to 64 tables.

 

1. 1. 20. How Do You See A Ddl For An Existing Table?

      By using show table command.

 

 

Database Administration Interview Questions

1. 1. 21. Which Is More Efficient Group By Or Distinct To Find Duplicates?

      With more duplicates GROUP BY is more efficient, if only a few duplicates exist DISTINCT is more efficient.

 

1. 1. 22. Syntax For Case When Statement?

      CASE value_expression_1 WHEN value_expression_n THEN scalar_expression_n
      END;

 

 

1. 1. 23. What’s The Difference Between Timestamp (0) And Timestamp (6)?

      TIMESTAMP (0) is CHAR (19) and TIMESTAMP (6) is CHAR (26)
      Everything is same except that TIMESTAMP (6) has microseconds too.

 

DB2 SQL Programming Interview Questions

1. 1. 24. How Do You Determine The Number Of Sessions?
      • Teradata performance and workload.
      • Client platform type, performance and workload.
      • Channel performance for channel attached systems.
      • Network topology and performance for network attached systems.
      • Volume of data to be processed by the application.

 

 

MySQL Interview Questions

1. 1. 25. What Is Node? How Many Nodes And Amps Used In Your Previous Project?

      Node is a database running in a server. We used 318 nodes and each node has 2 to 4 AMPS.

 

1. 1. 26. What Is A Clique?

      Clique is a group of disk arrays physically cabled to a group of nodes.

 

 

Hadoop Administration Interview Questions

1. 1. 27. What Is The Purpose Of Indexes?

      An index is a mechanism that can be used by the SQL query optimizer to make table access more performant. Indexes enhance data access by providing a moreor- less direct path to stored data and avoiding the necessity to perform full table scans to locate the small number of rows you typically want to retrieve or update.

 

Oracle 11g Interview Questions

1. 1. 28. What Is Primary Index And Secondary Index?

      Primary index is the mechanism for assigning a data row to an AMP and a location on the AMP’s disks. Indexes also used to access rows from a table without having to search the entire table. Secondary indexes enhance set selection by specifying access paths less frequently used than the primary index path. Secondary indexes are also used to facilitate aggregate operations.

      If a secondary index covers a query, then the Optimizer determines that it would be less costly to accesses its rows directly rather than using it to access the base table rows it points to. Sometimes multiple secondary indexes with low individual selectivity can be overlapped and bit mapped to provide enhanced.

 

1. 1. 29. What Are The Things To Be Considered While Creating Secondary Index?

      Creating a secondary index causes Teradata to build a sub-table to contain its index rows, thus adding another set of rows that requires updating each time a table row is inserted, deleted, or updated. Secondary index sub-tables are also duplicated whenever a table is defined with FALLBACK, so the maintenance overhead is effectively doubled.

 

Java Hadoop Developer Interview Questions

1. 1. 30. What Is Collect Statistics?

      Collects demographic data for one or more columns of a table, hash index, or join index, computes a statistical profile of the collected data, and stores the synopsis in the data dictionary. The Optimizer uses the synopsis data when it generates its table access and join plans.

 

1. 1. 31. Can We Collect Statistics On Multiple Columns?

      Yes we can collect statistics on multiple columns.

 

1. 1. 32. Can We Collect Statistics On Table Level?

      Yes we can collect statistics on table level. The syntax is COLLECT STAT ON TAB_A;

 

Informatica MDM Interview Questions

1. 1. 33. What Is Inner Join And Outer Join?

      An inner join gets data from both tables where the specified data exists in both tables. An outer join gets data from the source table at all times, and returns data from the outer joined table ONLY if it matches the criteria.

 

Hadoop Interview Questions

1. 1. 34. When Tpump Is Used Instead Of Multiload?

      TPump provides an alternative to MultiLoad for the low volume batch maintenance of large databases under control of a Teradata system. Instead of updating Teradata databases overnight, or in batches throughout the day, TPump updates information in real time, acquiring every bit of data from the client system with low processor utilization. It does this through a continuous feed of data into the data warehouse, rather than the traditional batch updates. Continuous updates results in more accurate, timely data. And, unlike most load utilities, TPump uses row hash locks rather than table level locks. This allows you to run queries while TPump is running. This also means that TPump can be stopped instantaneously. As a result, businesses can make better decisions that are based on the most current data.

 

1. 1. 35. What Is Spool Space And When Running A Job If It Reaches The Maximum Spool Space How You Solve The Problem?

      Spool space is used to hold intermediate rows during processing, and to hold the rows in the answer set of a transaction. Spool space reaches maximum when the query is not properly optimized. Use appropriate conditions in WHERE clause of the query to limit the answer set.

 

1. 1. 36. What Is Data Mart?

      A data mart is a special purpose subset of enterprise data used by a particular department, function or application. Data marts may have both summary and details data, however, usually the data has been pre aggregated or transformed in some way to better handle the particular type of requests of a specific user community. Data marts are categorized as independent, logical and dependant data marts.

 

TeraData DBA Interview Questions

1. 1. 37. Difference Between Star And Snowflake Schemas?

      Star schema is De-normalized and snowflake schema is normalized.

 

1. 1. 38. Why Are Oltp Database Designs Not Generally A Good Idea For A Data Warehouse?

      OLTP designs are for real time data and they are not normalized and preaggregated. They are not good for decision support systems.

 

1. 1. 39. What Type Of Indexing Mechanism Do We Need To Use For A Typical Data Warehouse?

      Primary Index mechanism is the ideal type of index for data warehouse.

 

1. 1. 40. What Is Real Time Data Warehousing?

      Real-time data warehousing is a combination of two things:
      

      1.  real-time activity and
      2.  data warehousing.

      Real-time activity is activity that is happening right now. The activity could be anything such as the sale of widgets. Once the activity is complete, there is data about it. Data warehousing captures business activity data. Real-time data warehousing captures business activity data as it occurs. As soon as the business activity is complete and there is data about it, the completed activity data flows into the data warehouse and becomes available instantly. In other words, real-time data warehousing is a framework for deriving information from data as the data becomes available.

 

MYSQL DBA Interview Questions

1. 1. 41. What Is Ods?

      An operational data store (ODS) is primarily a “dump” of relevant information from a very small number of systems (often just one) usually with little or no transformation. The benefits are an ad hoc query database, which does not affect the operation of systems required to run the business. ODS’s usually deal with data “raw” and “current” and can answer a limited set of queries as a result.

 

1. 1. 42. What Is Real Time And Near Real Time Data Warehousing?

      The difference between real time and near real time can be summed up in one word: latency. Latency is the time lag that is between an activity completion and the completed activity data being available in the data warehouse. In real time, the latency is negligible whereas in near real time the latency is a tangible time frame such as two hours.

 

Database Administration Interview Questions

1. 1. 43. What Are Normalization, First Normal Form, Second Normal Form And
      Third Normal Form?

      Normalization is the process of efficiently organizing data in a database. The two goals of the normalization process are eliminate redundant data (storing the same data in more than one table) and ensure data dependencies make sense (only storing related data in the table).

      First normalization form:
      

      • Eliminate duplicate columns from the same table.
      • Create separate tables for each group of related data and identify each row with a unique column or set of columns (primary key).

      Second normal form:
      

      • Removes sub set of data that apply to multiple rows of table and place them in separate table.
      • Create relationships between these new tables and their predecessors through the use of foreign keys.

      Third normal form:
      

      • Remove column that are not dependent upon the primary key.

 

1. 1. 44. What Is Fact Table?

      The centralized table in a star schema is called as FACT table i.e; a table in that contains facts and connected to dimensions. A fact table typically has two types of columns: those that contain facts and those that are foreign keys to dimension tables. The primary key of a fact table is usually a composite key that is made up of all of its foreign keys. A fact table might contain either detail level facts or facts that have been aggregated (fact tables that contain aggregated facts are often instead called summary tables). In the real world, it is possible to have a fact table that contains no measures or facts. These tables are called as Factless Fact tables.

 

1. 1. 45. What Is Etl?

      Extract, transformation, and loading. ETL refers to the methods involved in accessing and manipulating source data and loading it into target database. The first step in ETL process is mapping the data between source systems and target database (data warehouse or data mart). The second step is cleansing of source data in staging area. The third step is transforming cleansed source data and then loading into the target system. Note that ETT (extract, transformation, transportation) and ETM (extraction, transformation, move) are sometimes used instead of ETL.

 

1. 1. 46. What Is Er Diagram?

      It is Entity relationship diagram. Describes the relationship among the entities in the database model.

 

1. 1. 47. What Is Data Mining?

      Analyzing of large volumes of relatively simple data to extract important trends and new, higher level information. For example, a data-mining program might analyze millions of product orders to determine trends among top-spending customers, such as their likelihood to purchase again, or their likelihood to switch to a different vendor.

 

1. 1. 48. What Is Star Schema?

      Star Schema is a relational database schema for representing multi-dimensional data. It is the simplest form of data warehouse schema that contains one or more dimensions and fact tables. It is called a star schema because the entityrelationship diagram between dimensions and fact tables resembles a star where one fact table is connected to multiple dimensions. The center of the star schema consists of a large fact table and it points towards the dimension tables. The advantages of star schema are slicing down, performance increase and easy understanding of data.

 

1. 1. 49. What Is A Level Of Granularity Of A Fact Table?

      The components that make up the granularity of the fact table correspond directly with the dimensions of the data model. Thus, when you define the granularity of the fact table, you identify the dimensions of the data model. The granularity of the fact table also determines how much storage space the database requires. For example, consider the following possible granularities for a fact table:
      • Product by day by region
      • Product by month by region
      The size of a database that has a granularity of product by day by region would be much greater than a database with a granularity of product by month by region because the database contains records for every transaction made each day as opposed to a monthly summation of the transactions. You must carefully determine the granularity of your fact table because too fine a granularity could result in an astronomically large database. Conversely, too coarse granularity could mean the data is not detailed enough for users to perform meaningful queries against the database.

 

1. 1. 50. What Is A Dimension Table?

      Dimension table is one that describes the business entities of an enterprise, represented as hierarchical, categorical information such as time, departments, locations, and products. Dimension tables are sometimes called lookup or reference tables. In a relational data modeling, for normalization purposes, country lookup, state lookup, county lookup, and city lookups are not merged as a single table. In a dimensional data modeling (star schema), these tables would be merged as a single table called LOCATION DIMENSION for performance and slicing data requirements. This location dimension helps to compare the sales in one region with another region. We may see good sales profit in one region and loss in another region. If it is a loss, the reasons for that may be a new competitor in that area, or failure of our marketing strategy etc.

 

1. 1. 51. What Are The Various Reporting Tools In The Market?

      Crystal reports, Business objects, micro strategy and etc.,

 

1. 1. 52. What Are The Various Etl Tools In The Market?

      Ab Initio, Informatica and etc.

 

1. 1. 53. What Is A Three-tier Data Warehouse?

      The three-tier differs from the two-tier architecture by strictly enforcing a logical separation of the graphical user interface, business logic, and data. The three-tier is widely used for data warehousing today. Organizations that require greater performance and scalability, the three-tier architecture may be more appropriate. In this architecture, data extracted from legacy systems is cleansed, transformed, and stored in high –speed database servers, which are used as the target database for front-end data access.

 

1. 1. 54. Differentiate Primary Key And Partition Key?

      Primary Key is a combination of unique and not null. It can be a collection of key values called as composite primary key. Partition Key is a just a part of Primary Key. There are several methods of partition like Hash, DB2, and Random etc. While using Hash partition we specify the Partition Key.

 

1. 1. 55. Differentiate Database Data And Data Warehouse Data?

      Data in a Database is Detailed or Transactional, Both Readable and Write able and current.
      Data in data warehouse is detailed or summarized, storage place for historical data.

 

1. 1. 56. What Is Oltp?

      OLTP stands for Online Transaction Processing. OLTP uses normalized tables to quickly record large amounts of transactions while making sure that these updates of data occur in as few places as possible. Consequently OLTP database are designed for recording the daily operations and transactions of a business. E.g. a timecard system that supports a large production environment must record successfully a large number of updates during critical periods like lunch hour, breaks, startup and close of work.

 

1. 1. 57. What Is Staging Area?

      The data staging area is a system that stands between the legacy systems and the analytics system, usually a data warehouse and sometimes an ODS. The data staging area is considered the “back room” portion of the data warehouse environment. The data staging area is where the extract, transform and load (ETL) takes place and is out of bounds for end users. Some of the functions of the data staging area include:

      • Extracting data from multiple legacy systems.
      • Cleansing the data, usually with a specialized tool.
      • Integrating data from multiple legacy systems into a single data warehouse.
      • Transforming legacy system keys into data warehouse keys, usually surrogate keys.
      • Transforming disparate codes for gender, marital status, etc., into the data warehouse standard.
      • Transforming the heterogeneous legacy data structures to the data warehouse data structures.
      •  Loading the various data warehouse tables via automated jobs in a particular sequence through the bulk loader provided with the data warehouse database or a third-party bulk loader.

 

1. 1. 58. What Is Subject Area?

      Subject area means fundamental entities that make up the major components of the business, e.g. customer, product, employee.

 

1. 1. 59. What Is A Checkpoint?

      Checkpoints are entries posted to a restart log table at regular intervals during the data transfer operation. If processing stops while a job is running, you can restart the job at the most recent checkpoint.

 

1. 1. 60. What Is Slowly Changing Dimension?

      In a slowly changing dimension the attribute for a record varies over time. There are three ways to solve this problem.
      • Type 1 –
      Replace an old record with a new record. No historical data available.
      • Type 2 –
      Keep the old record and insert a new record. Historical data available but resources intensive.
      • Type 3 –
      In the existing record, maintain extra columns for the new values.

 

1. 1. 61. Difference Between Multiload And Tpump?

      Tpump provides an alternative to MultiLoad for low volume batch maintenance of large databases under control of a Teradata system. Tpump updates information in real time, acquiring every bit of a data from the client system with low processor utilization. It does this through a continuous feed of data into the data warehouse, rather than the traditional batch updates. Continuous updates results in more accurate, timely data. Tpump uses row hash locks than table level locks. This allows you to run queries while Tpump is running.

 

1. 1. 62. Different Phases Of Multiload?

      • Preliminary phase.
      • DML phase.
      • Acquisition phase.
      • Application phase.
      • End phase.

 

1. 1. 63. What Is Dimensional Modeling?

      Dimensional Data Modeling comprises of one or more dimension tables and fact tables. Good examples of dimensions are location, product, time, promotion, organization etc. Dimension tables store records related to that particular dimension and no facts (measures) are stored in these tables.

 

1. 1. 64. How Will You Solve The Problem That Occurs During Update?

      When there is an error during the update process, an entry is posted in the error log table. Query the log table and fix the error and restart the job.

 

1. 1. 65. Can You Connect Multiload From Ab Initio?

      Yes we can connect.

 

1. 1. 66. What Interface Is Used To Connect To Windows Based Applications?

      WinCLI interface.

 

1. 1. 67. What Is Data Warehousing?

      A data warehouse is a subject oriented, integrated, time variant, non-volatile collection of data in support of management’s decision-making process.

 

1. 1. 68. What Is Data Modeling?

      A Data model is a conceptual representation of data structures (tables) required for a database and is very powerful in expressing and communicating the business requirements.

 

1. 1. 69. What Is Logical Data Model?

      A Logical data model is the version of a data model that represents the business requirements (entire or part) of an organization and is developed before the physical data model. A sound logical design should streamline the physical design process by clearly defining data structures and the relationships between them. A good data model is created by clearly thinking about the current and future business requirements. Logical data model includes all required entities, attributes, key groups, and relationships that represent business information and define business rules.

 

1. 1. 70. Steps To Create A Data Model?
      •  Get business requirements.
      •  Create High Level Conceptual Data Model.
      •  Create Logical Data Model.
      •  Select target DBMS where data-modeling tool creates the physical schema.
      •  Create standard abbreviation document according to business standard.

 

1. 1. 71. What Is The Maximum Number Of Dml Can Be Coded In A Multiload Script?

      Maximum 5 DML can be coded in a MultiLoad script.

 

1. 1. 72. Does Sdlc Changes When You Use Teradata Instead Of Oracle?
      1. If the teradata is going to be only a data base means It won’t change the System development life cycle (SDLC).
      2. If you are going to use the teradata utilities then it will change the Architecture or SDLC.
      3. If your schema is going to be in 3NF then there won’t be huge in change.

 

1. 1. 73. How Many Codd’s Rules Are Satisfied By Teradata Database?

      There are 12 codd’s rules applied to the teradata database.

 

1. 1. 74. How Teradata Makes Sure That There Are No Duplicate Rows Being Inserted When Its A Set Table?

      Teradata will redirect the new inserted row as per its PI to the target AMP (on the basis of its row hash value), and if it find same row hash value in that AMP (hash synonyms) then it start comparing the whole row, and find out if duplicate. If its a duplicate it silently skips it without throwing any error.

 

1. 1. 75. What Is The Difference Between Global Temporary Tables And Volatile Temporary Tables?

      Global Temporary tables (GTT) –
      
      1. When they are created, its definition goes into Data Dictionary.
      2. When materialized data goes in temp space.
      3. thats why, data is active upto the session ends, and definition will remain there upto its not dropped using Drop table statement.
      If dropped from some other session then its should be Drop table all;
      4. you can collect stats on GTT.

      Volatile Temporary tables (VTT) –
      
      1. Table Definition is stored in System cache
      2. Data is stored in spool space.
      3. thats why, data and table definition both are active only upto session ends.
      4. No collect stats for VTT.

 

1. 1. 76. What Is Filler Command In Teradata?

      while using the mload of fastload if you dont want to load a particular filed in the datafile to the target then use this filler command to achieve this.

 

1. 1. 77. What Is The Command In Bteq To Check For Session Settings ?

      The BTEQ .SHOW CONTROL command displays BTEQ settings.

 

1. 1. 78. How Do You Set The Session Mode Parameters In Bteq?
      • set session transaction ANSI /* this is to set ANSI mode */
      • set session transaction BTET /* this is to set Teradata transaction mode */

 

1. 1. 79. How Many Types Of Index Are Present In Teradata?

      There are 5 different indices present in Teradata
      1. Primary Index.
      
      a.Unique primary index.
      b. non Unique primary index.
      2. Secondary Index.
      
      a. Unique Secondary index.
      b. non Unique Secondary index.
      3. Partitioned Primary Index.
      
      a. Case partition (ex. age, salary…).
      b. range partition ( ex. date).
      4. Join index.
      
      a. Single table join index.
      b. multiple table join index.
      c. Sparse Join index ( constraint applied on join index in where clause).
      5. Hash index.
      

 

1. 1. 80. What Does Sleep Function Does In Fast Load?

      The SLEEP command specifies the amount minutes to wait before retrying to logon and establish all sessions. Sleep command can be used with all load utilities not only fastload. This situation can occur if all of the loader slots are used or if the number of requested sessions is not available. The default value is 6 minutes. If tenacity was set to 2 hours and sleep 10 minutes, Sleep command will try to logon for every 10 minutes up to 2 hours duration.

 

1. 1. 81. What Are Types Of Partition Primary Index (ppi) In Teradata?

      1. Partition by CASE
      CREATE TABLE ORDER_Table
      (
      ORD_number integer NOT NULL,
      customer_number integer NOT NULL,
      Generated by Foxit PDF Creator © Foxit Software
      http://www.foxitsoftware.com For evaluation only.
      order_date date ,
      order_total integer
      )
      PRIMARY INDEX (customer_number)
      PARTITION BY case1 (
      order_total < 10000 ,
      order_total < 20000 ,
      order_total < 30000,
      NO CASE OR UNKNOWN ) ;
      2. Partition by Range – example using date range
      
      CREATE TABLE ORDER_Table
      (
      ORD_number integer NOT NULL,
      customer_number integer NOT NULL,
      order_date date ,
      order_total integer
      )
      PRIMARY INDEX (customer_number)
      PARTITION BY range1 (
      Order_date BETWEEN date ‘2010-01-01’ AND date ‘2010-12-01’
      EACH interval ‘1’ month ,
      NO RANGE OR UNKNOWN);

 

1. 1. 82. What Is A Sparse Index?

      Sparse Join Indexes are a type of Join Index which contains a WHERE clause that reduces the number of rows which would otherwise be included in the index. All types of join indexes, including single table, multitable, simple or aggregate can be sparse.

 

1. 1. 83. Difference Between Stored Procedure And Macro?

      Stored Procedure:
      

      • It does not return rows to the user.
      • It has to use cursors to fetch multiple rows
      • It used inout/Out to send values to user
      • It contains comprehensive SPL
      • It is stored in DATABASE or USER PERM
      • A stored procedure also provides output/Input capabilities

      Macros:
      

      • It returns set of rows to the user.
      • It is stored in DBC PERM space
      • A macro that allows only input values

 

1. 1. 84. What Is Difference B/w User And Database In Teradata?

      – User is a database with password but database cannot have password.
      – Both can contain Tables, views and macros.
      – Both users and databases may or may not hold privileges.
      – Only users can login, establish a session with Teradata database and they can submit requests.

 

1. 1. 85. What Are Differences Between Teradata And Ansi Session Modes In Teradata?

      TERADATA MODE:
      

      1. Comparison is not Case sensitive.
      2. Create table are default to SET tables.
      3. Each transaction is committed implicitly.
      4. Supports all Teradata commands.
      5. It follows BTET (Begin and End Transaction) Mode.

      ANSI MODE:
      

      1. Comparison is CASE sensitive.
      2. Create table are default to MULTISET tables.
      3. Each transaction has to be committed explicitly.
      4. Does not support all Teradata commands.
      5. It does not follow BTET Mode.

 

1. 1. 86. What Are The Scenarios In Which Full Table Scans Occurs?

      1. The where clause in SELECT statement does not use either primary index or secondary index.
      2. SQL Statement which uses a partial value (like or not like), in the WHERE statement.
      3. SQL Statement which does not contain where clause.
      4. SQL statement using range in where clause. Ex. (col1 > 40 or col1 < =10000).

 

1. 1. 87. How To Identify Ppi Columns?

      Select databasename , tablename , columnposition ,columnname from dbc.indices 
      where indextype ='Q'
      order by 1 ,2,3 ;

 

1. 1. 88. Can You Load Multiple Data Files For Same Target Table Using Fastload?

      Yes, we can Load a table using multiple datafiles in Fastload. Before giving “end loading” statement user can define file path and use insert sql for multiple source files and give “end loading” statement at the end.

 

1. 1. 89. Why Does Varchar Occupy 2 Extra Bytes?

      The two bytes are for the number of bytes for the binary length of the field. It stores the exact no of characters stored in varchar.

      .

 

1. 1. 90. What Do High Confidence, Low Confidence And No Confidence Mean In Explain Plan?

      Explain gives the execution strategy means what are the different steps that the query will go through.
      HIGH CONFIDENCE:
      Statistics are collected.
      LOW CONFIDENCE:
      Statistics are not collected. But the where condition is having the condition on indexed column. Then estimations can be based on sampling.
      NO CONFIDENCE:
      Statistics are not collected and the condition is on non indexed column.

 

1. 1. 91. How Can You Track Login Parameters Of Users In Teradata?

      SELECT LOGDATE, LOGTIME, USERNAME, EVENT FROM DBC.LOGONOFF;

 

1. 1. 92. What Are Tpump Utility Limitations?

      Following are the limitations of Teradata TPUMP Utility:
      

      • Use of SELECT statement is not allowed.
      •  Concatenation of Data Files is not supported.
      •  Exponential & Aggregate Operators are not allowed.
      •  Arithmatic functions are not supported.

 

1. 1. 93. What Are The Multiload Utility Limitations?

      MultiLoad is a very powerful utility; it has following limitations:
      

      • MultiLoad Utility doesn’t support SELECT statement.
      •  Concatenation of multiple input data files is not allowed.
      •  MultiLoad doesn’t support Arithmatic Functions i.e. ABS, LOG etc. in Mload Script.
      •  MultiLoad doesn’t support Exponentiation and Aggregator Operators i.e. AVG, SUM etc. in Mload Script.

 

1. 1. 94. What Are The Functions Of A Teradata Dba?

      Following are the different functions which a DBA can perform:
      1. User Management –
      Creation and managing Users, Databases, Roles, Profiles and Accounts.
      2. Space Allocation –
      Assigning Permanent Space, Spool Space and Temporary Space.
      3. Access of Database Objects –
      Granting and Revoking Access Rights on different database objects.
      4. Security Control –
      Handling logon and logoff rules for Users.
      5. System Maintenance –
      Specification of system defaults, restart etc.
      6. System Performance –
      Use of Performance Monitor(PMON), Priority Scheduler and Job Scheduling.
      7. Resource Monitoring
      – Database Query Log(DBQL) and Access Logging.
      8. Data Archives, Restores and Recovery –
      ARC Utility and Permanent Journals.

 

1. 1. 95. What Are The 5 Phases In A Multiload Utility?
      • Preliminary Phase – Basic Setup
      •  DML Phase – Get DML steps down on AMPs
      •  Acquisition Phase – Send the input data to the AMPs and sort it
      •  Application Phase – Apply the input data to the appropriate Target Tables
      •  End Phase – Basic Cleanup

 

1. 1. 96. How To View Every Column And The Columns Contained In Indexes In Teradata?

      Following query describes each column in the Teradata RDBMS

      SELECT * FROM DBC.TVFields;

      Following query describes columns contained in indexes in the Teradata RDBMS

      SELECT * FROM DBC.Indexes;

 

1. 1. 97. How To Select First N Records In Teradata?

      To select N records in Teradata you can use RANK function. Query syntax would be as follows

      SELECT BOOK_NAME, BOOK_COUNT, RANK(BOOK_COUNT)A FROM LIBRARY QUALIFY A <= 10;

 

1. 1. 98. How To Eliminate Product Joins In A Teradata Sql Query?

      1. Ensure statistics are collected on join columns and this is especially important if the columns you are joining on are not unique.
      2. Make sure you are referencing the correct alias.
      3. Also, if you have an alias, you must always reference it instead of a fully qualified tablename.
      4. Sometimes product joins happen for a good reason. Joining a small table (100 rows) to a large table (1 million rows) a product join does make sense.

 

1. 1. 99. How Does Hashing Happens In Teradata?
      • Hashing is the mechanism through which data is distributed and retrieved to/from AMPs.
      •  Primary Index (PI) value of a row is the input to the Hashing Algorithm.
      •  Row Hash (32-bit number) value is the output from this Algorithm.
      •  Table Id + Row Hash is used to locate Cylinder and Data block.
      •  Same Primary Index value and data type will always produce same hash value.
      •  Rows with the same hash value will go to the same AMP. So data distribution depends directly on the Row Hash uniqueness; be careful while Choosing Indexes in Teradata.

 

1. 1. 100. How Do You Transfer Large Amount Of Data In Teradata?

      Transferring of large amount of data can be done using various Application Teradata Utilities which resides on the host computer ( Mainframe or Workstation) i.e. BTEQ, FastLaod, MultiLoad, Tpump and FastExport.

      • BTEQ (Basic Teradata Query) supports all 4 DMLs: SELECT, INSERT, UPDATE and DELETE. BTEQ also support IMPORT/EXPORT protocols.
      •  Fastload, MultiLoad and Tpump transfer the data from Host to Teradata.
      •  FastExport is used to export data from Teradata to the Host.

 

1. 1. 101. How Can You Find The Teradata Release And Version Information From Data Dictionary Table?

      To find Release and Version information you can query this Data Dictionary table DBC.DBCINFO

      SELECT * FROM DBC.DBCINFO;

 

1. 1. 102. Can You Recover The Password Of A User In Teradata?

      No, you can’t recover the password of a user in Teradata. Passwords are stored in this data dictionary table (DBC.DBASE) using a one-way encryption method. You can view the encrypted passwords using the following query.

      SELECT * FROM DBC.DBASE;

 

1. 1. 103. What Are The Types Of Tables In Teradata ?

      1. set table.
      2. multiset table.
      3. derived table.
      4. global temporary table(temporary table).
      5. volatile table.

 

1. 1. 104. In A Table Can We Use Primary Key In One Column And In Another Column Both Unique And Not Null Constrains.if Yes How?

      Yes, you can have a column for Primary key and have another column which will have no duplicates or null. e.g. A Salary Table will have employee ID as primary key. The table also contains TAX-ID which can not be null or duplicate.

 

1. 1. 105. Can I Use “drop” Statement In The Utility “fload”?

      YES,But you have to declare it out of the FLOAD Block it means it should not come between .begin loading,.end loading FLOAD also supports DELETE,CREATE,DROP statements which we have to declare out of FLOAD blocking the FLOAD Block we can give only INSERT.

 

1. 1. 106. Can We Load A Multi Set Table Using Mload?

      We can Load SET, MULTISET tables using Mload, But here when loading into MULTISET table using MLOAD duplicate rows will not be rejected, we have to take care of them before loading.But in case of Fload when we are loading into MULTISET duplicate rows are automatically rejected, FLOAD will not load duplicate rows weather table is SET or MULTISET.

 

1. 1. 107. Teradata Performance Tuning And Optimization?

      1. collecting statistics.
      2. Explain Statements.
      3. Avoid Product Joins when possible.
      4. select appropriate primary index to avoid skewness in storage.
      5. Avoid Redistribution when possible.
      6. Use sub-selects instead of big “IN” lists.
      7. Use derived tables.
      8. Use GROUP BY instead of DISTINCT ( GROUP BY sorts the data locally on the VPROC. DISTINCT sorts the data after it is redistributed).
      9. Use Compression on large tables.

 

1. 1. 108. What Is An Optimization And Performance Tuning And How Does It Really Work In Practical Projects?

      Performance tuning and optimization of a query involves collecting statistics on join columns, avoiding cross product join, selection of appropriate primary index (to avoid skewness in storage) and using secondary index.

 

1. 1. 109. What Are The Enhanced Features In Teradata V2r5 And V2r6?

      V2R6 included the feature of replica in it. in which copy of data base are available on another system which means V2R6 provide the additional data protection as comparison to V2R5 while if data from one system has been vanishes.

 

1. 1. 110. What Is A Common Data Source For The Central Enterprise Data Warehouse?

      ODS=>Operational Data Source.

 

1. 1. 111. What Are The Basic Rules That Define How Pi Is Defined In Teradata?

      The following rules govern how Primary Indexes in a Teradata Database must be defined as well as how they function:
      One Primary Index per table.
      A Primary Index value can be unique or non-unique.
      The Primary Index value can be NULL.
      The Primary Index value can be modified.
      The Primary Index of a populated table cannot be modified.
      A Primary Index has a limit of 64 columns.

 

1. 1. What Types Of Joint Ventures Are There?

   There are many examples of collaborations between businesses – common ones are the following structures where two or more people share resources and risk:

   1. setting up a separate Joint Venture company where each party has a shareholding and can appoint directors to carry out a specific (and often finite) project such as development of a new product
   2. contractual arrangements such as entering into a distribution agreement
   3. forming a partnership
   4. merging two businesses.

   The rest of this article covers the first structure above where each person in the Joint Venture has a shareholding and appoints directors.

2. 2. Who Will Be Part Of The Joint Venture?

   The people contributing the assets to the Joint Venture, or JV, will all be parties to the Joint Venture Agreement.

Financial Accounting Interview Questions

3. 3. Will The Joint Venture Company Or Other Vehicle Itself Be A Party To The Joint Venture Agreement?

   Usually, Yes so that shareholders can enforce against the company.

4. 4. What Issues Do I Need To Consider When Looking For A Joint Venture Partner?

   • Look for a JV partner with complementary strengths: eg a software product which you can distribute through the Joint Venture.
   • Take time to understand fully what your partner’s purpose and objectives will be from the JV.  You will need to be able to agree objectives that suit both of you.
   • You will also need to reach agreement on a whole range of other issues as well as the JV agreement.
   • Consider at the outset what happens when the JV comes to an end. This  can make it difficult to collaborate with a competitor or with a business that is likely to compete with you in the future.

Tally Tutorial

5. 5. How Do I Negotiate Heads Of Terms?

   The Heads Terms document sets out the main principles for the Joint Venture and the steps and documents required to get it set up. Read more about negotiating Heads of Terms Agreements.

Tally

6. 6. What Is The Best Way To Structure A Joint Venture?

   1. Usually the JV parties form a separate limited company for the Joint Venture  so each has limited liability (up to amount of share capital invested) should the Joint Venture  not work and become insolvent.
   2. However the tax position must be assessed to start with because transferring significant assets into the Joint Venture can have unwanted tax consequences. You should check with your tax advisers.
   3. Sometimes a partnership or a limited liability partnership is used instead.
   4. If you do not require management involvement in the  Joint Venture, it may be best to use contractual arrangements rather than to create a separate Joint Venture  entity.

   • For example
     , a designer could simply license his or her intellectual property rights in the design to another business to exploit in return for royalty payments. You should identify what other agreements are needed between the Joint Venture and the shareholders – eg licences to use software, brand names, premises, secondment of staff etc.

7. 7. What About Financing Joint Ventures?

   You and your Joint Venture partner will need to agree:

   • What proportion (if any) of the initial finance will the parties themselves provide and how much will be provided from external sources.
   • If third party funding is being sought, what security and/or recourse to the parties themselves will the lender(s) require.
   • Will the parties’ initial investment be in cash and/or by contributing assets.
   • If the funding will be through debt rather than equity, or vice versa.

   What arrangements will there be for funding, on a continuing basis:

   1.  the working capital requirements
   2.  losses incurred by the joint venture; and/or
   3.  development and expansion costs

   • Will each party be required (or entitled) to contribute to continuing calls for funding, pro-rata to its original investment or otherwise
   • What happens if one of the parties defaults.

Security Analysis and Investment Management Tutorial
Security Analysis and Investment Management

8. 8. What Assets Can Be Put Into Joint Ventures?

   Any asset can be put into a Joint Venture e.g. employees, intellectual property, offices, customers and suppliers and their related contracts.

   Contributions can be by outright transfer, or by a lease or licence to the Joint Venture for a fixed or indefinite term. Separate documents will be required for the transfer of each asset to the Joint Venture .

   The contributed assets will need to be valued and agreed with the Joint Venture partner.

   You will need to agree if all contributions of assets can be made simultaneously, if you need any regulatory approvals or consents third parties (including lessors, licensors and lenders) or how required for any transfer. If not, the availability of all or any particular asset(s) can be a condition precedent to the establishment of the Joint Venture.

9. 9. What Legal Agreements Are Needed To Set Up A Joint Venture?

   If you are forming a new Joint Venture  company, a Joint Venture Agreement and the new company’s articles of association are crucial.

   Points that may be covered in these documents or in separate agreements include:

   • the financing arrangements for the Joint Venture
   • agreements not to compete with the Joint Venture
   • arrangements for licensing or transferring intellectual property in inventions, brands, designs or copyright works such as plans or manuals to the Joint Venture
   • agreements on any services or supplies you will provide to the Joint Venture
   • confidentiality agreements
   • how any disputes will be handled
   • how the partners can exit the Joint Venture
   • any agreements that will continue after the Joint Venture is terminated.

Working Capital Management

10. 10. What Is A Shareholders Agreement?

    A Shareholders Agreement can be another name for the Joint Venture Agreement. It sets out the agreement between the shareholders showing how they will operate the Joint Venture, how they will make decisions and vote as the shareholders and directors.

Working Capital Management Tutorial

11. 11. What Are The Shareholders Rights In A Joint Venture?

    The shareholders will need to agree:

    • How will ownership of the Joint Venture will be divided and what voting rights the parties will  have as shareholders
    • If there will be separate classes of shares – eg because each class of shares will have different ownership, dividends and or voting rights
    • If shares of the same class will be capable of being held by more than one person
    • If there will be any special voting rights attached to any or all shares
    • What quorum and notice requirements will apply for shareholder meetings
    • if there be any limitation on possible locations for shareholders’ meetings

Business Development

12. 12. What Is Minority Shareholder Protection In A Joint Venture?

    If a shareholder owns less than say 50% of the Joint Venture it may want to protect itself in the following circumstances:

    The majority shareholder forcing through voting on certain important issues at shareholder meetings ( e.g. changing the business, adding new shareholders, issuing new shares, buying new businesses or selling parts of the business)

    Similar protections and any remedies can apply to board and/or director level voting as well.

Financial Accounting Interview Questions

13. 13. How Do We Take Profits From The Joint Venture?

    Profits from Joint Venture companies are commonly distributed through dividends.

    Of course, the ability of the Joint Venture  to pay dividends will depend on its cashflow position. Depending on the circumstances, there may also be other more tax-effective ways of realizing part of the value of your investment in the Joint Venture. Where a Joint Venture is structured as a partnership, profits are automatically shared between the partners as specified in the partnership agreement. The partnership agreement should also specify what cash payments partners can take from the partnership. If there is no separate joint venture entity, there will be no need to ‘take’ profits from the joint venture – the profits will in any case arise within your (or your Joint Venture partner’s) business.

14. 14. Give The Journal Entry Under The Method Where Separate Set Of Books Is Kept When Cash Contributed Or Invested Or Paid- In-by Co- Ventures?

     Joint Bank A/C  Dr                xxx 

    To Respective Co-venture A/C          xxx

15. 15. What Are The Disadvantages Of Joint Venture?

    • Setting unrealistic objectives that may not be completely clear in advance and not aligned to a common goal.
    • Making poor tactical decisions caused by a misunderstanding of the roles of each company.

Taxation

16. 16. What Is The Difference Between Joint Venture And Consignment?

    • The parties to a joint venture are called co- ventures whereas the parties to a consignment are called consignor and consignee.
    • In a joint venture all the co- ventures bear the risk whereas in consignment only the consignor bears the risk.

17. 17. What Is The Difference Between Joint Venture And Partnership?

    Joint Venture involves two or more companies joining together in business. In partnership, it is individuals who join together for a combined venture.

FAA Construction

18. 18. Name The Accounts Prepared Under The Method Where No Separate Set Of Books Is Kept ?

    • Joint Venture Account 
    • Other Co- ventures Account

Tally

19. 19. What Is Co- Ventures Account?

    This is the capital account of the venture relating to venture. This account is credited by the capital contributed by the ventures, goods supplied by them from their own stock, expenses made personally by them etc whereas this account is debited for any withdrawal or any asset taken from the venture.

20. 20. What Is Joint Venture Account?

    This account represents the results of the business, that is, profit or loss. This account is debited by the cost of goods, expenses,goods supplied by the ventures etc and are credited by sale proceeds, unsold stock, stock taken by ventures etc.

Legal outsourcing

21. 21. Explain The Meaning Of Memorandum Joint Venture Account?

    It is prepared through memoranda i.e. transactions are directly entered in the Memorandum Joint Venture Account. It is merely a statement showing profit or loss on venture.

22. 22. What Is Joint Venture?

    A joint venture is a business arrangement in which two or more parties agree to pool their resources for the purpose of accomplishing a specific task.This task can be a new project or any other business activity.The venture is its own entity, separate and apart from the participant’s other business interests.

1. 1. What Is Jms?

   JMS means Java Messaging Service.  It is the new standard for inter client communication. It allows the J2EE application component to create, send, read and receive the messages.

2. 2. What Type Of Messaging Is Provided By Jms?

   JMS provides both type of messaging,

   • synchronous
   • Asynchronous

Simple Mail Transfer Protocol (SMTP) Interview Questions

3. 3. What Do You Mean By Synchronous And Asynchronous Type Of Messaging?

   Synchronous:
   In this type of messaging, client waits for the server to respond to a message. Ex: Telephone call, two way radio communication.
   Asynchronous:
   In this type of messaging, client does not wait for a message from the server, but automatically an event is created to trigger a message from a server. Ex: email, text messaging, blog posting.

4. 4. How Many Types Of Messaging Model Do Jms Provide For And What Are They?

   There are two types of messaging models that JMS provides –

   • Point to point queuing
   • Second one is public and subscribe

JavaMail API Tutorial

5. 5. Mention Different Types Of Messages Available In Jms Api?

   The different types of messages available in JMS API are Message, TextMessage, BytesMessage, ObjectMessage and MapMessage.

JavaMail API

6. 6. What Is The Difference Between The P2p (peer To Peer) Model And Subscribe Model?

   P2P model is highly reliable and it is used in a one-to-one situation, while subscribe model is used in one-to-many situation. It is very fast but less reliable.

7. 7. What Is A Jms Client?

   JMS client is a language program that sends or receives messages.

JNDI (Java Naming and Directory Interface)

8. 8. Can We Send E-mail Messages Using Jms?

   JMS has no inherent support for email operations.

9. 9. Explain How Application Server Handles The Jms Connection?

   •With the help of Application server, the server session is created and it stores them in a pool
   •To put messages in JMS session, connection consumer, uses the Server session
   •Server session is the one that creates the JMS session
   •Application written by Application programmers creates the message listener.

Java Management Extensions (JMX)

10. 10. What Is The Difference Between Jms And Rpc (remote Procedure Call)?

    The basic difference between JMS and RPC lies in the way they message. JMS uses asynchronous messaging type while, RPC creates synchronous messaging type. The method invoker in RPC, waits for the method to finish execution and return back the control to the invoker. In JMS the message sender just sends the message to the destination and continues its own processing.

11. 11. Explain How Does The Jms Work With The J2ee?

    The application client like enterprise JavaBeans components and web components can send or receive JMS message synchronously. In addition, the application clients can also receive message asynchronously.   With the help of message-driven beans, JMS provider can optionally implement the processing of messages. Message-driven beans are a type of enterprise bean that enables the asynchronous consumption of messages.
    The operation of sending and receiving message is carried out in distributed operation, which allows JMS operations and database accesses within a single transaction.

Mail Server

12. 12. What Are The Types Of Messages That Are Supported By Jms?

    The types of messages that are supported by JMS are
    •Stream Messages
    •Text Messages
    •Map Messages
    •Bytes Messages
    •Object Messages

Simple Mail Transfer Protocol (SMTP) Interview Questions

13. 13. What Is Mom In Reference To Jms?

    The MOM ( Message Oriented Middleware) is a software that works as an intermediate between two communicating components.  It is placed between the client and server, MOM provides the facility of passing message by using the technique queuing. Until the client does not request to read the message, the messages will be stored in queue.  By using this technique, the software component can work independently of time.

14. 14. How You Can Deliver A Java Message To A Non-java Client?

    First of all, after receiving the message from Topic or Queue, the message has to be converted into a non-java client according to their specification. The message once converted to non-java client, it can be delivered.

15. 15. For Sending Messages Through Jms, What Encryption Options Are There?

    The encryption and decryption of the messages is handled by JMS provider and not JMS specifications. Sonic MQ by Progress Software is a leading JMS provider and they do encryption through encryption mechanisms called Quality of Protection.

     

Apache Wicket

16. 16. For Jms-enabled Application, What Are The Core Jms-related Objects Required?

    The core JMS-related objects that are required are –
    •The connection object
    •One or more sessions within a connection that provides a context for message sending and receiving.
    •A topic or queue object within a session representing the destination within the message broker.
    •Appropriate sender or publisher or receiver within a session.

17. 17. What Is Jms Administered Object?

    JMS administered object is a pre-configured JMS object that is created by an administrator for the use of JMS clients and placed in JNDI namespace.

18. 18. What Is The Important Part Of Jms Applications?

    •Session
    •Connection
    •Message
    •Message Producer
    •Message Consumer
    •Connection factory and destination

JavaMail API

19. 19. What Is Jms Session?

    A JMS session is a single-threaded context for sending and receiving JMS messages.  A JMS session could be a locally transacted, non-transacted or distributed transacted.

20. 20. Mention The Difference Between Durable And Non-durable Subscription?

    Durable subscription gives a subscriber the freedom of receiving all messages from a topic, while a non-durable subscription does not make any guarantees about messages sent by others when a client get disconnected by others.

21. 21. What Is Byte Message?

    Byte message is a stream of uninterrupted bytes. It contains an array of primitive bytes in its payload.  For the transfer of data between two applications in their native format, byte message is used, which may be not possible with other message types.

22. 22. Give An Example Of Using Point To Point Model In Jms?

    Example for point to point model, would be a print out. When you select a print-out option, your system sends the message to the server, and once the print-out is taken out, again this server will send the message back to you. Point to point model is used, when the information is specific to a single client.

23. 23. What Is The Role Of The Jms Provider?

    The JMS provider handles data conversion, security of the messages and the client triggering.  It specifies the level of encryption, security level of the message and the best-data type for the non-JMS client.

24. 24. What Are The Components Of Jms?

    •JMS provider
    •JMS client
    •Messages
    •Administered objects
    •Native clients

JNDI (Java Naming and Directory Interface)

25. 25. What Is The Jms Api?

    The Java Message Service is a Java API that allows applications to create, send, receive, and read messages. Designed by Sun and several partner companies, the JMS API defines a common set of interfaces and associated semantics that allow programs written in the Java programming language to communicate with other messaging implementations.
    The JMS API minimizes the set of concepts a programmer must learn to use messaging products but provides enough features to support sophisticated messaging applications. It also strives to maximize the portability of JMS applications across JMS providers in the same messaging domain.
    The JMS API enables communication that is not only loosely coupled but also
    Asynchronous.
    A JMS provider can deliver messages to a client as they arrive; a client does not have to request messages in order to receive them.
    Reliable
    . The JMS API can ensure that a message is delivered once and only once. Lower levels of reliability are available for applications that can afford to miss messages or to receive duplicate messages.
    The JMS Specification was first published in August 1998. The latest version of the JMS Specification is Version 1.1, which was released in April 2002. You can download a copy of the Specification from the JMS Web site, http://java.sun.com/products/jms/.

26. 26. How Jms Is Different From Rpc?

    In RPC the method invoker waits for the method to finish execution and return the control back to the invoker. Thus it is completely synchronous in nature. While in JMS the message sender just sends the message to the destination and continues it’s own processing. The sender does not wait for the receiver to respond. This is asynchronous behavior. 

27. 27. How May Messaging Models Do Jms Provide For And What Are They?

    JMS provides for two messaging models, publish-and-subscribe and point-to-point queuing. 

Java Management Extensions (JMX)

28. 28. What Is The Point-to-point Model In Jms?

    A point-to-point model is based on the concept of a message queue: Senders send messages into the queue, and the receiver reads messages from this queue. In the point-to-point model, several receivers can exist, attached to the same queue. However, (Message Oriented Middleware)MOM will deliver the message only to one of them. To which depends on the MOM implementation. 

29. 29. What Is The Publish-and-subscribe Model In Jms?

    A publish-subscribe model is based on the message topic concept: Publishers send messages in a topic, and all subscribers of the given topic receive these messages. 

30. 30. What Is Publish/subscribe Messaging?

    With publish/subscribe message passing the sending application/client establishes a named topic in the JMS broker/server and publishes messages to this queue. The receiving clients register (specifically, subscribe) via the broker to messages by topic; every subscriber to a topic receives each message published to that topic. There is a one-to-many relationship between the publishing client and the subscribing clients. 

31. 31. Which Models Are Supported By Jms? Please, Explain Them.

    Publish/subscribe (pub/sub). This model allows a client (publisher) to send messages to a JMS topic. These messages are retrieved by other clients (subscribers) (it may happen so that a topic has no subscribers) asynchronously. Pub/sub model requires a broker distributing messages to different consumers. 

32. 32. What Are The Different Parts Of A Jms Message?

    A JMS message contains three parts. a header, an optional properties and an optional body. 

33. 33. What Is The Main Parts Of Jms Applications?

    The main parts of JMS applications are:

    • ConnectionFactory and Destination
    • Connection
    • Session
    • MessageProducer
    • MessageConsumer
    • Message 

Mail Server

34. 34. What Is The Difference Between Java Mail And Jms Queue?

    JMS is the ideal high-performance messaging platform for intrabusiness messaging, with full programmatic control over quality of service and delivery options.
    JavaMail provides lowest common denominator, slow, but human-readable messaging using infrastructure already available on virtually every computing platform.

35. 35. Does Jms Specification Define Transactions? Queue

    JMS specification defines a transaction mechanisms allowing clients to send and receive groups of logically bounded messages as a single unit of information. A Session may be marked as transacted. It means that all messages sent in a session are considered as parts of a transaction. A set of messages can be committed (commit() method) or rolled back (rollback() method). If a provider supports distributed transactions, it’s recommended to use XAResource API. 

     

36. 36. What Is Messaging?

    Messaging is a method of communication between software components or applications. A messaging system is a peer-to-peer facility: A messaging client can send messages to, and receive messages from, any other client. Each client connects to a messaging agent that provides facilities for creating, sending, receiving, and reading messages.
    Messaging enables distributed communication that is loosely coupled. A component sends a message to a destination, and the recipient can retrieve the message from the destination. However, the sender and the receiver do not have to be available at the same time in order to communicate. In fact, the sender does not need to know anything about the receiver; nor does the receiver need to know anything about the sender. The sender and the receiver need to know only what message format and what destination to use. In this respect, messaging differs from tightly coupled technologies, such as Remote Method Invocation (RMI), which require an application to know a remote application’s methods.
    Messaging also differs from electronic mail (e-mail), which is a method of communication between people or between software applications and people. Messaging is used for communication between software applications or software components.
    Messaging is a mechanism by which data can be passed from one application to another application. 

Apache Wicket

37. 37. What Is Synchronous Messaging? Queue

    Synchronous messaging involves a client that waits for the server to respond to a message. So if one end is down the entire communication will fail. 

38. 38. What Is Asynchronous Messaging? Queue

    Asynchronous messaging involves a client that does not wait for a message from the server. An event is used to trigger a message from a server. So even if the client is down , the messaging will complete successfully. 

     

39. 39. How Does A Typical Client Perform The Communication? Queue

    1. Use JNDI to locate administrative objects.
    2. Locate a single ConnectionFactory object.
    3. Locate one or more Destination objects.
    4. Use the ConnectionFactory to create a JMS Connection.
    5. Use the Connection to create one or more Session(s).
    6. Use a Session and the Destinations to create the MessageProducers and MessageConsumers needed.
    7. Perform your communication. 

40. 40. What Is Jms Application?

    One or more JMS clients that exchange messages. 

1. 1. Can I Look Inside Of An Oven And Measure The Target Temperature?

   Yes, but you have to consider reflection. Usually the oven is hotter than the target and the target has some reflectivity, so the infrared thermometer measures the emitted energy of the hot target, as well as the reflected energy of the oven walls or heaters, causing the indication to read too high.

   This problem may be eliminated using a system called background compensation where the instrument and software will subtract the reflected energy and provide temperature based on the real target energy. The second choice is to measure the target at the exit of the oven. For glass, plastic films, food and paper applications, selection of the right thermometer can eliminate the reflection problem without background compensation or viewing at the exit of the oven.

2. 2. Can Ir Sensors See Through Dust And Smoke?

   Infrared thermometers cannot see through these interferences. However, in most industrial applications, the dust and smoke are rising from the hot object. If our eyes were as fast as an IR thermometer, we would see openings where the instrument has a clear line of sight. With the aid of a function called a peak picker, the IR instrument can detect the target temperature and ignore the cold readings caused by dust and smoke.

Electronics and Communications Engineering Interview Questions

3. 3. Does The Sensor Have To Be Aimed Perpendicular To The Surface?

   No, often looking at a low angle allows you to avoid obstructions in the optical path or high ambient conditions. When viewing rough surfaces like hot strip steel, the sensor can be aimed 15º from the horizontal. When viewing glass, plastic or paper, the lowest angle allowed is 45º.

4. 4. How Critical Is Focusing The Ir Instrument?

   All infrared thermometers resolve a specific target size based on the model of the instrument and the distance from the sensor to the target. Ideally the target should be 2 times larger than the spot size in order to indicate the correct temperature. If the target is smaller than the resolved spot, then the instrument will measure everything that is filling the remainder of the target. These principles do not apply to two-color ratio thermometer.

Power Electronics Tutorial

5. 5. What Can I Do If The Ambient Temperature Requires Water-cooling, But I Have No Water Available?

   Consider the use of an instrument with a fiber optic sensor. The fiber can be as long as 22 m (72 ft) and can operate in an environment up to 600ºF (315ºC) without cooling.

Power Electronics

6. 6. What Are The Smallest Target Ir Sensors Can Measure?

   IR sensors measure targets as small as .43mm (.017 in). The limitation is the temperature and emissivity. As the temperature goes lower or the emissivity is lower, then the instrument cannot go as small in spot size. The sensor will have to be placed closer to the target and a close focus lens will have to be utilized.

7. 7. How Does Distance To Target Affect The Ir Sensor?

   As the IR sensor is placed further from the target, the spot size measured by the sensor becomes bigger. The target has to be large or small enough for the instrument to view it and measure correctly, depending on the application.

Electronics

8. 8. What Is A Two-color Pyrometer?

   A two-color pyrometer an instrument that measures the energy in two different wavelength bands (colors) in order to determine temperature. A two-color pyrometer is often called a ratio thermometer because the temperature is measured by calculating the ratio between the two detector signals. The two color technique used in this instrument has been shown to be effective for correcting errors due to partial blockage of the target caused by smoke and dust particles, a dirty lens, or the target not filling the resolved spot size.

9. 9. What Is The Effect Of Scale On The Surface Of Steel?

   If the scale is tightly bonded to the steel it will usually have no effect because it is the same temperature as the hot target. However, if the scale breaks loose, it will cool and cause a cold spot on the target. If the instrument is a single wavelength instrument, it will indicate a low temperature. If the instrument is a two color and only a portion of the spot is filled with the cold scale, it usually will not affect the temperature indication.

ELECTRONICS & INSTRUMENTATION Engineering

10. 10. Will Color Of The Measured Object Affect The Measurement?

    For instruments that operate from the visible to 2.6 microns, the color will usually change the emissivity. For wavelengths longer than 3 microns, the color will not affect the emissivity. However, color does affect heating. Dark objects will get hotter than light colored objects.

11. 11. Can An Infrared Sensor Be Overcooled?

    Yes, the IR sensor can get overcooled because the air inside the sensor contains moisture. If overcooled, the moisture will condense; fill the sensor with water eventually destroying it.

Electronic Devices and Circuits

12. 12. How Critical Is Water On The Surface Of The Target I’m Measuring?

    Usually infrared thermometers cannot see thru water so the temperature indication may be very erratic. If the water layer is intermittent then consider the use of the peak picker. The peak picker will allow the instrument to detect the real target temperature when the water is not present and hold the real temperature when there is water in the line of sight. This provides a continuous and accurate temperature indication.

Electronics and Communications Engineering Interview Questions

13. 13. How Do I Calibrate My Instrument?

    Infrared thermometers are calibrated on a standard called a Blackbody. If a blackbody is not available, consider the use of a transfer standard. This is an infrared thermometer that is calibrated and certified, and is used to compare to the online instrument. This instrument should be calibrated and certified each year.

14. 14. How Often Should Ir Sensors Be Calibrated?

    It is common practice for IR instruments that have ISO calibration to be checked on a blackbody once a year.

15. 15. My Portable And Online Ir Sensors Indicate Different Temperatures. Which One Is Right?

    Usually different temperature readings are caused by emissivity. Most likely, the portable thermometer has a different wavelength and emissivity settings from the online instrument. You need to set the correct emissivity for both instruments and also verify correct distance to spot ratio.

Industrial Instrumentation

16. 16. What Happens If The Ir Sensor Is Overheated?

    Every sensor has an upper ambient temperature limit that is allowed without cooling. If this temperature is exceeded, the instrument will begin to provide erratic or incorrect temperature indications. If the sensor gets extremely hot, it will be destroyed. For hot environments above sensor’s standard ambient operating temperatures, air or water-cooling cooling accessories are available.

17. 17. What Is A Peak Picker?

    Most infrared thermometers have peak picker function. There are many applications where the target is intermittent or there are intermittent interferences, such as steam and smoke. As the hot target fills the spot momentarily, a peak is obtained. The peak picker holds this peak until another peak comes along. This allows the instrument to provide a continuous indication even though the target is intermittent.

18. 18. What Is E Slope?

    On a two color thermometer, the instrument relies on a ratio between two detectors. Often this ratio is affected by interferences that affect one wavelength and not the other, as for example, when Pyrex is used for a window instead of the recommended quartz. To correct the ratio, a control is used to add a signal to one of the detectors to make it indicate the correct temperature. This correction is only needed to be set once for a specific application.

Power Electronics

19. 19. Why Does The Instrument Indicate Too Low Of Temperature?

    If you suspect too low temperature readings, you need to check for: Incorrect emissivity Dirty lens or window incorrect focusing of the instrument blocked line of sight by an obstruction.