Oracle 10g Interview Questions with Answers
Question: 1. What Is Oracle 10g?
Answer:
Oracle 10g is a model of the Oracle Database. The g stands for “grid” to suggest that 10g is “grid-computing ready”.
Question: 2. Why Is A Union All Faster Than A Union?
Answer:
The union operation, you will don’t forget, brings sets of information together. It will *NOT* but produce duplicate or redundant rows. To perform this feat of magic, a SORT operation is accomplished on both tables. This is manifestly computationally in depth, and uses massive memory as nicely. A UNION ALL conversely just dumps collection of each units together in random order, now not stressful approximately duplicates.
Oracle 9i Interview Questions
Question: 3. What Are Some Advantages To Using Oracle’s Create Database Statement To Create A New Database Manually?
Answer:
You can script the technique to consist of it in a fixed of deploy scripts you supply with a product.
You can positioned your create database script in CVS for model control, in order you make modifications or modifications to it, you could music them like you do adjustments to software code.
You can log the output and evaluate it for mistakes. You study greater about the technique of database introduction, which include what alternatives are available and why.
Question: four. What Are The Pros And Cons Of Using Triggers?
Answer:
A cause is one or greater statements of SQL that are being performed in occasion of information change in a table to which the trigger belongs.
Triggers enhance the security, performance, and standardization of databases.
Triggers can be useful while used:
to check or alter values earlier than they are truely updated or inserted inside the database. This is beneficial if you want to convert data from the manner the person sees it to a few internal database layout.
To run different non-database operations coded in consumer-defined capabilities
to update information in different tables. This is beneficial for maintaining relationships among records or in keeping audit path records.
To test towards different data inside the desk or in different tables. This is beneficial to ensure statistics integrity while referential integrity constraints aren’t suitable, or whilst desk test constraints restriction checking to the cutting-edge desk best.
Oracle 10g Tutorial
Question: 5. When A Query Is Sent To The Database And An Index Is Not Being Used, What Type Of Execution Is Taking Place?
Answer:
A desk scan.
Oracle 8i Interview Questions
Question: 6. What Is The Difference Of A Left Join And An Inner Join Statement?
Answer:
A LEFT JOIN will take ALL values from the primary declared table and matching values from the second one declared table primarily based at the column the be a part of has been declared on. An INNER JOIN will take best matching values from each tables
Question: 7. What Is An Advantage To Using A Stored Procedure As Opposed To Passing An Sql Query From An Application.
Answer:
A stored procedure is pre-loaded in reminiscence for faster execution. It lets in the DBMS manage of permissions for protection purposes. It also eliminates the need to recompile additives when minor changes arise to the database.
Oracle 9i Tutorial Informatica Interview Questions
Question: 8. What Is A Cartesian Product? What Causes It?
Answer:
A Cartesian product is the result of an unrestricted be part of of or greater tables. The result set of a 3 desk Cartesian product could have x * y * z range of rows where x, y, z correspond to the number of rows in each table involved within the be a part of. It is causes by means of specifying a table within the FROM clause without becoming a member of it to some other table.
Question: nine. What Is The Maximum Number Of Triggers, Can Apply To A Single Table?
Answer:
12 triggers.
PL/SQL Interview Questions
Question: 10. What Is The Output Of Sign Function?
Answer:
1 for nice fee,
0 for Zero,
-1 for Negative price.
Oracle 8i Tutorial
Question: eleven. What Are The More Common Pseudo-columns?
Answer:
SYSDATE, USER , UID, CURVAL, NEXTVAL, ROWID, ROWNUM
Oracle 11g Interview Questions
Question: 12. What Are Pl/sq. Cursor Exceptions?
Answer:
Cursor_Already_Open, Invalid_Cursor
Oracle 9i Interview Questions
Question: thirteen. Any Three Pl/square Exceptions?
Answer:
Too_many_rows,
No_Data_Found,
Value_Error,
Zero_Error,
Others
Informatica Tutorial
Question: 14. Which Date Function Returns Number Value?
Answer:
months_between
Question: 15. Display Odd/ Even Number Of Records
Answer:
Odd quantity of statistics:
select * from emp where (rowid,1) in (pick rowid, mod(rownum,2) from emp);
1
three
5
Even range of records:
choose * from emp where (rowid,0) in (pick out rowid, mod(rownum,2) from emp)
2
4
6
SQL Interview Questions
Question: sixteen. To View Installed Oracle Version Information
Answer:
SQL> pick out banner from v$version;
Oracle 11g Tutorial
Question: 17. Find Out Nth Highest Salary From Emp Table
Answer:
SELECT DISTINCT (a.Sal) FROM EMP A WHERE &N = (SELECT COUNT (DISTINCT (b.Sal)) FROM EMP B WHERE a.Sal<=b.Sal);
Enter value for n: 2
SAL
—————
3700
Oracle apps Interview Questions
Question: 18. Explicit Cursor Attributes
Answer:
There are four cursor attributes used in Oracle
cursor_name%Found,
cursor_name%NOTFOUND,
cursor_name%ROWCOUNT,
cursor_name%ISOPEN
Oracle 8i Interview Questions
Question: 19. How Do I Display Row Number With Records?
Answer:
To achive this use rownum pseudocolumn with query, like
SQL> select rownum, ename from emp;
Output:
—————–
1 Scott
2 Millor
three Jiyo
four Smith
Question: 20. Switch To Dos Prompt
Answer:
SQL> host
Sybase Interview Questions
Question: 21. To See Current User Name
Answer:
Sql> display user;
Question: 22. If A View On A Single Base Table Is Manipulated Will The Changes Be Reflected On The Base Table?
Answer:
If adjustments are made to the tables and those tables are the bottom tables of a view, then the changes can be reference at the view.
Question: 23. Can A View Be Updated/inserted/deleted? If Yes – Under What Conditions?
Answer:
A View can be updated/deleted/inserted if it has only one base table if the view is based totally on columns from one or greater tables then insert, update and delete is not feasible.
Oracle Apps ERP Interview Questions
Question: 24. What Are The Advantages Of View?
Answer:
– To defend some of the columns of a desk from other customers.
– To conceal complexity of a question.
– To conceal complexity of calculations.
Informatica Interview Questions
Question: 25. What Is Cycle/no Cycle In A Sequence?
Answer:
CYCLE specifies that the collection hold to generate values after accomplishing both most or minimal value. After pan-ascending sequence reaches its most cost, it generates its minimal price. After a descending collection reaches its minimum, it generates its most.
NO CYCLE specifies that the series can not generate more values after attaining its most or minimal price.
Question: 26. How To Access The Current Value And Next Value From A Sequence? Is It Possible To Access The Current Value In A Session Before Accessing Next Value?
Answer:
Sequence call CURRVAL, collection call NEXTVAL. It isn’t viable. Only in case you get entry to subsequent fee inside the consultation, modern fee can be accessed.
Oracle 7.Three Interview Questions
Question: 27. What Is A Database Link?
Answer:
Database link is a named route via which a far off database can be accessed.
PL/SQL Interview Questions
Question: 28. If Unique Key Constraint On Date Column Is Created, Will It Validate The Rows That Are Inserted With Sysdate?
Answer:
It received’t, Because SYSDATE layout consists of time attached with it.
Question: 29. How Will You Activate/deactivate Integrity Constraints?
Answer:
The integrity constraints may be enabled or disabled via ALTER TABLE ENABLE CONSTRAINT / DISABLE CONSTRAINT.
Oracle Access Manager Interview Questions
Question: 30. Where The Integrity Constraints Are Stored In Data Dictionary?
Answer:
The integrity constraints are stored in USER_CONSTRAINTS.
Question: 31. What Are The Pre-standards To Modify Datatype Of A Column And To Add A Column With Not Null Constraint?
Answer:
– To regulate the datatype of a column the column need to be empty.
– To upload a column with NOT NULL constrain, the desk should be empty.
Question: 32. How Many Long Columns Are Allowed In A Table? Is It Possible To Use Long Columns In Where Clause Or Order By?
Answer:
Only one LONG column is allowed. It isn’t viable to use LONG column in WHERE or ORDER BY clause.
Oracle Application Framework Interview Questions
Question: 33. What Is Difference Between Char And Varchar2? What Is The Maximum Size Allowed For Each Type?
Answer:
CHAR pads clean spaces to the maximum duration.
VARCHAR2 does not pad blank spaces.
For CHAR the most period is 255 and 2000 for VARCHAR2.
Oracle 11g Interview Questions
Question: 34. What Are The Data Types Allowed In A Table?
Answer:
CHAR, VARCHAR2, NUMBER, DATE, RAW, LONG and LONG RAW.
Question: 35. What Is On Delete Cascade?
Answer:
When ON DELETE CASCADE is detailed Oracle continues referential integrity by means of routinely putting off dependent foreign key values if a referenced number one or specific key value is removed.
Question: 36. What Is The Usage Of Savepoints?
Answer:
SAVEPOINTS are used to subdivide a transaction into smaller components. It enables rolling again a part of a transaction. Maximum of 5 save factors are allowed.
SQL Interview Questions
Question: 37. What Is Referential Integrity Constraint?
Answer:
Maintaining facts integrity thru a fixed of rules that restrict the values of one or greater columns of the tables based totally at the values of number one key or unique key of the referenced table.
Question: 38. What Is An Integrity Constraint?
Answer:
Integrity constraint is a rule that restricts values to a column in a desk.
Question: 39. What Is Rowid?
Answer:
ROWID is a pseudo column attached to every row of a desk. It is 18 characters lengthy, blockno, rownumber are the components of ROWID.
Question: 40. Explain Union, Minus, Union All And Intersect?
Answer:
INTERSECT – returns all distinct rows decided on by both queries.
MINUS – returns all awesome rows selected by means of the primary question but now not by means of the second one.
UNION – returns all distinct rows selected through both query
UNION ALL – returns all rows decided on with the aid of either query, such as all duplicates.
Oracle apps Interview Questions
Question: 41. Difference Between Substr And Instr?
Answer:
INSTR (String1, String2 (n, (m)),
INSTR returns the position of the m-th incidence of the string 2 in string1. The seek starts from nth position of string1.
SUBSTR (String1 n, m)
SUBSTR returns a person string of size m in string1, starting from n-th role of string1.
Question: 42. Explain Connect By Prior?
Answer:
Retrieves rows in hierarchical order
eg: pick empno, ename from emp in which.
Sybase Interview Questions
Question: 43. What Is Correlated Sub-query?
Answer:
Correlated sub-question is a sub-question, which has connection with the primary question.
Question: 44. What Is The Sub-question?
Answer:
Sub-query is a query whose go back values are utilized in filtering conditions of the primary question.
Question: 45. What Is A Join? Explain The Different Types Of Joins?
Answer:
Join is a query, which retrieves associated columns or rows from multiple tables.
Self Join – Joining the table with itself.
Equi Join – Joining tables by equating two common columns.
Non-Equi Join – Joining two tables by way of equating commonplace columns.
Outer Join – Joining two tables in this type of way that query also can retrieve rows that do not have corresponding be part of price inside the different table.
Question: forty six. What Is Difference Between Truncate & Delete?
Answer:
TRUNCATE commits after deleting complete desk i.E., cannot be rolled again.
Database triggers do no longer fireplace on TRUNCATE
DELETE lets in the filtered deletion. Deleted information can be rolled lower back or devoted.
Database triggers fireplace on DELETE.
Question: forty seven. What Is A Transaction?
Answer:
Transaction is logical unit between commits and devote and rollback.
Question: forty eight. What Are The Types Of Sql Statement?
Answer:
Data Definition Language: CREATE, ALTER, DROP, TRUNCATE, REVOKE, NO AUDIT & COMMIT.
Data Manipulation Language: INSERT, UPDATE, DELETE, LOCK TABLE, EXPLAIN PLAN & SELECT.
Transactional Control: COMMIT & ROLLBACK.
Session Control: ALTERSESSION & SET ROLE.
System Control: ALTER SYSTEM.
Question: forty nine. What Are The Dictionary Tables Used To Monitor A Database Space?
Answer:
DBA_FREE_SPACE
DBA_SEGMENTS
DBA_DATA_FILES.
SQL*Plus Statements
Question: 50. How Will You Enforce Security Using Stored Procedures?
Answer:
Don’t supply consumer get right of entry to at once to tables in the application.
Instead grant the capability to get admission to the techniques that get entry to the tables.
When system performed it’s going to execute the privilege of tactics proprietor. Users can not get entry to tables except via the procedure.
Question: 51. What Is User Account In Oracle Database?
Answer:
A consumer account is not a bodily shape in database but it’s far having vital courting to the gadgets within the database and may be having positive privileges.
Question: fifty two. List The Factors That Can Affect The Accuracy Of The Estimations?
Answer:
– The area used transaction entries and deleted facts, does not emerge as unfastened straight away after of entirety due to not on time cleanout.
– Trailing nulls and length bytes are not saved.
– Inserts of, updates to and deletes of rows as well as columns larger than a unmarried statistics block, can reason fragmentation a chained row pieces.
Question: 53. What Are Disadvantages Of Having Raw Devices?
Answer:
We need to rely upon export/import software for backup/recuperation (fully dependable)
The tar command can’t be used for bodily document backup, as a substitute we are able to use dd command, that’s less bendy and has restrained recoveries.
Question: 54. When Will Be A Segment Released?
Answer:
When Segment is dropped.
When Shrink (RBS best)
When truncated (TRUNCATE used with drop garage alternative)
Question: fifty five. What Is Hit Ratio?
Answer:
It is a measure of nicely the statistics cache buffer is managing requests for facts.
Hit Ratio = (Logical Reads – Physical Reads – Hits Misses)/ Logical Reads.
Question: fifty six. What Is A Rollback Segment Entry?
Answer:
It is the set of earlier than image statistics blocks that contain rows which can be changed by using a transaction.
Each rollback segment access have to be finished inside one rollback section.
A single rollback phase can have more than one rollback segment entries.
Question: fifty seven. What Is Use Of Rollback Segments In Oracle Database?
Answer:
They allow the database to maintain examine consistency between multiple transactions.
Question: 58. What Is Advantage Of Having Disk Shadowing / Mirroring?
Answer:
Shadow set of disks keep as a backup within the event of disk failure. In maximum running structures if any disk failure occurs it mechanically switchover to location of failed disk.
Improved performance because most OS guide quantity shadowing can direct record I/O request to apply the shadow set of documents as opposed to the main set of files. This reduces I/O load on the primary set of disks.
Question: fifty nine. What Is Redo Log File Mirroring? How Can Be Achieved?
Answer:
Process of having a duplicate of redo log documents is known as mirroring.
This can be completed by growing institution of log files collectively, in order that LGWR will routinely writes them to all the contributors of the current on-line redo log institution. If anybody group fails then database robotically switch over to next group. It degrades overall performance.
Question: 60. How To Implement The Multiple Control Files For An Existing Database?
Answer:
Shutdown the database
Copy one of the current controlfile to new region
Edit Config ora report through including new manipulate filename
Restart the database.
Question: 61. What Is A Control File?
Answer:
Database’s basic physical architecture is maintained in a document known as control report. It might be used to hold inner consistency and guide recovery operations. Multiple copies of manage files are advisable.
Question: 62. It Is Possible To Use Raw Devices As Data Files And What Are The Advantages Over File System Files?
Answer:
The advantages over document device documents are that I/O could be stepped forward because Oracle is bye-passing the kernel which writing into disk. Disk corruption can be very less.
Question: sixty three. How Can We Plan Storage For Very Large Tables?
Answer:
Limit the range of extents within the desk
Separate desk from its indexes.
Allocate enough temporary garage.
Question: 64. How Will You Monitor The Space Allocation?
Answer:
By querying DBA_SEGMENT table/view
Question: 65. Why Query Fails Sometimes?
Answer:
Rollback phase dynamically quantity to deal with large transactions entry loads.
A single transaction may additionally wipeout all to be had loose space within the rollback segment tablespace. This prevents different consumer the use of rollback segments.
Question: sixty six. How The Space Utilization Takes Place Within Rollback Segments?
Answer:
It will attempt to fit the transaction in a cyclic fashion to all present extents. Once it determined an quantity is in use then it compelled to acquire a new extent (wide variety of extents is based on the choicest length)
Question: 67. How Will You Create Multiple Rollback Segments In A Database?
Answer:
– Create a database, which implicitly creates a SYSTEM rollback phase in a SYSTEM tablespace.
– Create a second rollback phase call R0 inside the SYSTEM tablespace.
– Make new rollback segment available (after shutdown, alter init.Ora report and start database)
– Create different tablespaces (RBS) for rollback segments.
– Deactivate rollback phase R0 and set off the newly created rollback segments.
Question: 68. What Is The Functionality Of System Table Space?
Answer:
To manage the database level transactions including modifications of the records dictionary desk that file data approximately the loose space utilization.
Question: 69. What Is The Optimal Parameter?
Answer:
It is used to set the greatest duration of a rollback phase.
Question: 70. What Is The Role Of Pctfree Parameter Is Storage Clause?
Answer:
This is used to reserve positive quantity of space in a block for growth of rows.
Question: seventy one. How Does Space Allocation Table Place Within A Block?
Answer:
Each block consists of entries as follows
Fixed block header
Variable block header
Row Header, row date (more than one rows may exists)
PCTEREE (% of unfastened space for row updating in future)
Question: 72. What Is The Significance Of Having Storage Clause?
Answer:
We can plan the garage for a table as how an awful lot preliminary extents are required, how an awful lot may be extended subsequent, how an awful lot % have to go away unfastened for coping with row updating, and many others.,
Question: seventy three. Which Parameter In Storage Clause Will Reduce Number Of Rows Per Block?
Answer:
PCTFREE parameter
Row length additionally reduces no of rows in step with block.
Question: 74. What Is Meant By Free Extent?
Answer:
A loose extent is a collection of continuous loose blocks in tablespace. When a section is dropped its extents are reallocated and are marked as free.
Question: seventy five. How Will You Force Database To Use Particular Rollback Segment?
Answer:
SET TRANSACTION USE ROLLBACK SEGMENT rbs_name.
Question: seventy six. List The Optional Flexible Architecture (ofa) Of Oracle Database? How Can We Organize The Tablespaces In Oracle Database To Have Maximum Performance?
Answer:
SYSTEM – Data dictionary tables.
DATA – Standard operational tables.
DATA2- Static tables used for standard operations
INDEXES – Indexes for Standard operational tables.
INDEXES1 – Indexes of static tables used for wellknown operations.
TOOLS – Tools table.
TOOLS1 – Indexes for gear table.
RBS – Standard Operations Rollback Segments,
RBS1,RBS2 – Additional/Special Rollback segments.
TEMP – Temporary motive tablespace
TEMP_USER – Temporary tablespace for users.
USERS – User tablespace.
Question: seventy seven. How Will You Swap Objects Into A Different Table Space For An Existing Database?
Answer:
– Export the person
– Perform import the use of the command imp machine/manager file=export.Dmp indexfile=newrite.Square. This will create all definitions into newfile.Sq..
– Drop necessary objects.
– Run the script newfile.Sq. After altering the tablespaces.
– Import from the backup for the essential objects.
Question: seventy eight. What Is Redo Log Buffer?
Answer:
Changes made to the facts are written to the online redo log files. So that they can be utilized in roll forward operations in the course of database recoveries. Before writing them into the redo log files, they may first delivered to redo log buffers in SGA and LGWR will write into files frequently. LOG_BUFFER parameter will decide the scale.
Question: seventy nine. What Is Meant By Recursive Hints?
Answer:
Number of times tactics repeatedly query the dictionary table is called recursive hints. It is due to the records dictionary cache is simply too small. By growing the SHARED_POOL_SIZE parameter we are able to optimize the size of information dictionary cache.
Question: 80. What Is Dictionary Cache?
Answer:
Dictionary cache is facts approximately the database items stored in a information dictionary table.
Question: 81. What Is Database Buffers?
Answer:
Database buffers are cache in the SGA used to maintain the facts blocks that are study from the records segments within the database inclusive of tables, indexes and clusters DB_BLOCK_BUFFERS parameter in INIT.ORA comes to a decision the scale.
Question: eighty two. What Are The Factors Causing The Reparsing Of Sql Statements In Sga?
Answer:
Due to inadequate shared pool size.
Monitor the ratio of the reloads takes vicinity at the same time as executing SQL statements. If the ratio is greater than 1 then boom the SHARED_POOL_SIZE.
Database Logical & Physical Architecture
Question: eighty three. What Is A Data Segment?
Answer:
Data phase are the physical areas inside a database block wherein the records associated with tables and clusters are stored.
Question: eighty four. What Is Mean By Program Global Area (pga)?
Answer:
It is location in memory this is used by a unmarried Oracle person method.
Question: 85. What Is A Shared Pool?
Answer:
Shared pool in oracle contains cache statistics that collects, parses, interprets and executes SQL statements that goes in opposition to database. This shared pool acts like a buffer for these SQL statements.
Question: 86. What Is Sga?
Answer:
The System Global Area in an Oracle database is the region in reminiscence to facilitate the switch of information between customers. It holds the maximum currently asked structural facts among users. It holds the maximum these days asked structural information approximately the database. The structure is database buffers, dictionary cache, redo log buffer and shared pool place.
Question: 87. What Is A Cluster Key?
Answer:
The associated columns of the tables are referred to as the cluster key. The cluster secret’s listed the usage of a cluster index and its fee is saved only once for more than one tables within the cluster.
Question: 88. What Are Clusters?
Answer:
Group of tables physically saved collectively due to the fact they proportion common columns and are regularly used collectively is called cluster.
Question: 89. What Is An Index? How It Is Implemented In Oracle Database?
Answer:
An index is a database structure used by the server to have direct get admission to of a row in a desk. An index is mechanically created when a completely unique of primary key constraint clause is specified in create desk command
Question: 90. What Is A Schema?
Answer:
The set of objects owned via person account is called the schema.
Question: ninety one. What Is Parallel Server?
Answer:
Multiple times gaining access to the equal database (handiest in multi-CPU environments)
Question: ninety two. What Is A Database Instance? Explain.
Answer:
A database example (Server) is a fixed of reminiscence structure and history techniques that get entry to a hard and fast of database files. The techniques can be shared with the aid of all the customers.
The reminiscence structure this is used to shop the most queried statistics from database. This facilitates up to enhance database overall performance by means of reducing the quantity of I/O achieved in opposition to records record.
Question: ninety three. What Is The Use Of Control File?
Answer:
When an instance of an Oracle database is commenced, its control document is used to become aware of the database and redo log files that ought to be opened for database operation to continue. It is also used in database recovery.
Question: ninety four. What Does A Control File Contains?
Answer:
– Database call
– Names and locations of a database’s documents and redolog documents.
– Time stamp of database advent.
Question: 95. What Is The Use Of Redo Log Information?
Answer:
The facts in a redo log record is used simplest to recover the database from a machine or media failure prevents database information from being written to a database’s facts files.
Question: ninety six. What Is The Function Of Redo Log?
Answer:
The number one feature of the redo log is to file all modifications made to records.
Question: ninety seven. What Is A Redo Log?
Answer:
The set of redo log files for a database is together known as the database redo log.
Question: ninety eight. What Are The Characteristics Of Data Files?
Answer:
A information report can be related to most effective one database. Once created a information file can’t exchange size. One or extra statistics documents shape a logical unit of database storage called a tablespace.
Question: 99. What Is A Datafile?
Answer:
Every Oracle database has one or extra bodily data files. A database’s records files comprise all the database information. The records of logical database systems including tables and indexes is bodily saved within the statistics documents allocated for a database.
Question: 100. What Is A Temporary Segment?
Answer:
When the statement finishes execution, the brief phase extents are released to the system for destiny use.
Question: one hundred and one. What Are The Uses Of Rollback Segment?
Answer:
To generate read-regular database facts at some point of database recuperation and to rollback uncommitted transactions by way of the customers.
Question: 102. What Is Rollback Segment?
Answer:
A database incorporates one or more rollback segments to briefly shop “undo” statistics.
Question: 103. What Is An Index Segment?
Answer:
Each index has an index segment that stores all of its facts.
Question: 104. What Are The Different Types Of Segments?
Answer:
Data segment, index segment, rollback phase and brief section.
Question: one zero five. What Is A Segment?
Answer:
A section is a hard and fast of extents allotted for a sure logical shape.
Question: 106. What Is An Extent?
Answer:
An volume is a specific range of contiguous facts blocks, obtained in a unmarried allocation and used to keep a specific type of records.
Question: 107. What Is Row Chaining?
Answer:
In instances, all of the statistics for a row in a table may not be able to fit inside the identical data block. When this occurs, the information for the row is saved in a series of statistics block (one or greater) reserved for that phase.
Question: 108. How To Define Data Block Size?
Answer:
A records block length is distinctive for every Oracle database whilst the database is created. A database users and allotted unfastened database space in Oracle facts blocks. Block length is laid out in init.Ora report and cannot be changed latter.
Question: 109. What Is Data Block?
Answer:
Oracle database’s information is saved in facts blocks. One facts block corresponds to a specific number of bytes of physical database area on disk.
Question: one hundred ten. What Is Network Database Link?
Answer:
Network database link is created and managed by using a community area provider. A community database hyperlink may be used while any person of any database inside the community specifies a international object call in a SQL declaration or item definition.
Question: 111. What Is Public Database Link?
Answer:
Public database link is created for the special person group PUBLIC. A public database hyperlink may be used whilst any consumer in the related database specifies a international object name in a SQL announcement or item definition.
Question: 112. What Is Private Database Link?
Answer:
Private database link is created on behalf of a particular user. A personal database link may be used only whilst the proprietor of the hyperlink specifies a global object name in a SQL declaration or within the definition of the proprietor’s views or strategies.
Question: 113. What Are The Types Of Database Links?
Answer:
Private database link, public database hyperlink & community database link.
Question: 114. What Is Database Link?
Answer:
A database hyperlink is a named object that describes a “direction” from one database to some other.
Question: a hundred and fifteen. When Can Hash Cluster Used?
Answer:
Hash clusters are higher choice while a table is often queried with equality queries. For such queries the required cluster key value is hashed. The ensuing hash key fee factors immediately to the place on disk that shops the specified rows.
Question: 116. What Is Hash Cluster?
Answer:
A row is saved in a hash cluster based on the end result of applying a hash feature to the row’s cluster key cost. All rows with the equal hash key price are stores collectively on disk.
Question: 117. What Is Index Cluster?
Answer:
A cluster with an index at the cluster key.
Question: 118. What Is Cluster Key?
Answer:
The related columns of the tables in a cluster are known as the cluster key.
Question: 119. How Are The Index Updates?
Answer:
Indexes are robotically maintained and used by Oracle. Changes to desk records are routinely incorporated into all relevant indexes.
Question: 120. What Is An Oracle Index?
Answer:
An index is an non-obligatory shape related to a desk to have direct access to rows, which can be created to growth the overall performance of facts retrieval. Index may be created on one or extra columns of a desk.
Question: 121. What Are Synonyms Used For?
Answer:
– Mask the real name and owner of an object.
– Provide public access to an object
– Provide area transparency for tables, views or application gadgets of a remote database.
– Simplify the SQL statements for database customers.
Question: 122. What Is A Public Synonym?
Answer:
Any database consumer can get right of entry to a public synonym.
Question: 123. What Is A Private Synonym?
Answer:
Only its proprietor can get admission to a personal synonym.
Question: 124. What Are The Types Of Synonyms?
Answer:
There are forms of synonyms personal and public.
Question: a hundred twenty five. What Is A Synonym?
Answer:
A synonym is an alias for a desk, view, sequence or software unit.
Question: 126. What Is An Oracle Sequence?
Answer:
A collection generates a serial listing of specific numbers for numerical columns of a database’s tables.
Question: 127. What Are The Advantages Of Views?
Answer:
Provide an extra level of desk safety, by means of restricting get entry to to a predetermined set of rows and columns of a table.
Hide information complexity.
Simplify instructions for the user.
Present the statistics in a distinct angle from that of the bottom table.
Store complex queries.
Question: 128. Can A View Based On Another View?
Answer:
Yes.
Question: 129. Do A View Contain Data?
Answer:
Views do no longer contain or shop statistics.
Question: a hundred thirty. What Is An Oracle View?
Answer:
A view is a digital table. Every view has a question attached to it. (The question is a SELECT announcement that identifies the columns and rows of the table(s) the view uses.)
Question: 131. What Is Oracle Table?
Answer:
A desk is the primary unit of data garage in an Oracle database. The tables of a database keep all of the consumer on hand facts. Table information is stored in rows and columns.
Question: 132. Can A Tablespace Hold Objects From Different Schemes?
Answer:
Yes.
Question: 133. Can Objects Of The Same Schema Reside In Different Tablespaces?
Answer:
Yes.
Question: 134. What Are Schema Objects?
Answer:
Schema gadgets are the logical systems that directly talk to the database’s data. Schema gadgets include tables, views, sequences, synonyms, indexes, clusters, database triggers, procedures, functions packages and database links.
Question: a hundred thirty five. What Is Schema?
Answer:
A schema is series of database items of a consumer.
Question: 136. Explain The Relationship Among Database, Tablespace And Data File.
Answer:
Each databases logically divided into one or more tablespaces one or extra statistics files are explicitly created for each tablespace.
Question: 137. What Is System Tablespace And When Is It Created?
Answer:
Every Oracle database includes a tablespace named SYSTEM, which is mechanically created when the database is created. The SYSTEM tablespace usually includes the data dictionary tables for the entire database.
Question: 138. What Is A Tablespace?
Answer:
A database is divided into Logical Storage Unit known as tablespaces. A tablespace is used to grouped related logical systems collectively.
Question: 139. What Are The Components Of Logical Database Structure Of Oracle Database?
Answer:
There are tablespaces and database’s schema gadgets.
Question: 140. What Are The Components Of Physical Database Structure Of Oracle Database?
Answer:
Oracle database is created from 3 sorts of documents. One or greater datafiles, two are more redo log files, and one or more manage documents.