SAP ABAP Data Dictionary Interview Questions for freshers experienced :-
1. What is an ABAP Data dictionary?
ABAP dictionary is a central data management system. Its main function is to support the creation and management of data definitions.
2. What is a Size Category?
The Size category describes the probable space requirement of the table in the database.
3. How Many types of size categories and data classes are there?
There are five size categories (0-4) and 11 data classes, only three of which are appropriate for application tables:
- APPL0 – Master data (data frequently accessed but rarely updated)
- APPL1 – Transaction data (data that is changed frequnetly)
- APPL2 – Organisational data (customizing data that is entered when system is configured and then rarely changed)
4. What are control tables?
The values specified for the size category and data class are mapped to database-specific values via control tables.
5. What is the function of the transport system and workbench organiser?
The function of the transport system and the Workbench Organizer is to manage any changes made to objects of the ABAP/4 Development Workbench and to transport these changes between different SAP systems.
6. What is a table pool?
A table pool (or pool) is used to combine several logical tables in the ABAP/4 Dictionary. The definition of a pool consists of at least two key fields and a long argument field (VARDATA).
7. What are pooled tables?
These are logical tables which must be assigned to a table pool when they are defined. Pooled tables can be used to store control data (such as screen sequences or program parameters).
8 .What is a table cluster?
A table cluster combines several logical tables in the ABAP/4 Dictionary.Several logical rows from different cluster tables are brought together in a single physical record. The records from the cluster tables assigned to a cluster are thus stored in a single common table in the database.
9. Which objects are independent transport objects?
Domains, Data elements, Tables, Technical settings for tables,Secondary indexes for transparent tables, Structures, Views,Matchcode objects, Matchcode IDs, Lock objects.
10. What are the Data types of the external layer?
ACCP, CHAR, CLNT, CUKY,CURR, DATS, DEC, FLTP, INT1,INT2, INT4, LANG, LCHR,LRAW, NUMC, PREC, QUAN,RAW ,TIMS, UNIT, VARC.
11. What are the Data types of the ABAP/4 layer?
Possible ABAP/4 data types:
C: Character.
D: Date, format YYYYMMDD.
F: Floating-point number in DOUBLE PRECISION (8 bytes).
I: Integer.
N: Numerical character string of arbitrary length.
P: Amount or counter field (packed; implementation depends on hardware platform).
S: Time stamp YYYYMMDDHHMMSS.
T: Time of day HHMMSS.
V: Character string of variable length, length is given in the first two bytes.
X: Hexadecimal (binary) storage.
12. How can we set the tablespaces and extent sizes ?
You can specify the extent sizes and the tablespace (physical storage area in the database) in which a transparent table is to be stored by setting the size category and data class.
13. What are the basic objects of the data dictionary?
- Tables
- Domains
- Data elements
- Structures
- Foreign keys
14. What functions does a data dictionary perform ?
In a data management system, the principal functions performed by the data dictionary are:
- Management of data definitions
- Provision of information for evaluation
- Support for software development
- Support form documentation
- Ensuring that the data definitions are flexible and up-to-date.
15. A field containing currency amounts (data type CURR) must be assigned to a reference table and a reference field. Explain.?
- As a reference table, a system table containing all the valid currencies is assigned or any other table which contains a field with the currency key format. This field is called as reference field.
- The assignment of the field containing currency amounts to the reference field is made at runtime. The value in the reference field determines the currency of the amount.
16. What is the significance of Technical settings (specified while creating a table in the data dictionary) ?
By specifying technical settings we can control how database tables are created in the database.
The technical settings allows us to
optimize storage space requiremnets
table access behaviour
buffering required
changes to entries logged
17. What is the significance of Delivery Class ?
The delivery class controls the degree to which the SAP or the customer is responsible for table maintenance
- whether SAP provides the table with or without contents.
- determines the table type.
- determines how the table behaves when it is first installed, at upgrade, when it is transported, and when a client copy is performed.
18. What is the maximum number of structures that can be included in a table or structure
Nine.
19. What are the two methods of modifying Sap standard tables ?
- Append Structures and
- Customizing Includes.
20. What is the difference between a Substructure and an Append Structure ?
In case of a substructure, the reference originates in the table itself, in the forma of a statement .include… .
In case of an append structure, the table itself remains unchanged and the refrence originates in the append structure.
21. What are the two ways for restricting the value range for a domain ?
- By specifying fixed values.
- By stipulating a value table.
22. What is a Match Code ?
Match Code is a tool to help us to search for data records in the system. Match codes are an efficient and user-friendly search aid where key of a record is unknown.
23. What are the two levels in defining a Match Code ?
- Match Code object
- Match Code Id.
24.What is the maximum number of match code Id’s that can be defined for one Match code object ?
36. A match code Id is a one character ID which can be a letter or a number.
25. Can we define our own Match Code ID’s for SAP Matchcodes ?
Yes, the numbers 0 to 9 are reserved for us to create our own Match Code IDs for a SAP defined Matchcode object.
26. What is an Update type with reference to a Match code ID?
If the data in one of the base tables of a matchcode ID changes, the matchcode data has to be updated. The update type stipulates when the matchcode is to be updated and how it is to be done. The update type also specifies which method is to be used for Building matchcodes . You must specify the update type when you define a matchcode ID.
27. What are conversion routines ?
Non standard conversions from display format to sap internal format and vice-versa are implemented with so called conversion routines.
28. What are Aggregated Objects
Views, matchcodes, and lock objects are also called aggregate objects because they are formed from several related tables.
29. What is a View ?
A view is a logical view on one or more tables. A view on one or more tables i.e, the data from a view is not actually physically stored instead being derived from one or more tables. A view can be used to summarize data which is distributed among several tables
30. How many types of Views are there ?
Database View (SE11)
Database views are implement an inner join, that is, only records of the primary table (selected via the join operation) for which the corresponding records of the secondary tables also exist are fetched. Inconsistencies between primary and secondary table could, therefore, lead to a reduced selection set.
In database views, the join conditions can be formulated using equality relationships between any base fields. In the other types of view, they must be taken from existing foreign keys. That is, tables can only be collected in a maintenance or help view if they are linked to one another via foreign keys.
Help View ( SE54)
Help views are used to output additional information when the online help system is called.
When the F4 button is pressed for a screen field, a check is first made on whether a matchcode is defined for this field. If this is not the case, the help view is displayed in which the check table of the field is the primary table. Thus, for each table no more than one help view can be created, that is, a table can only be primary table in at most one help view.
Projection View
Projection views are used to suppress or mask certain fields in a table (projection), thus minimizing the number of interfaces. This means that only the data that is actually required is exchanged when the database is accessed.
A projection view can draw upon only one table. Selection conditions cannot be specified for projection views.
Maintenance View ( SE54 )
Maintenance views enable a business-oriented approach to looking at data, while at the same time, making it possible to maintain the data involved. Data from several tables can be summarized in a maintenance view and maintained collectively via this view. That is, the data is entered via the view and then distributed to the underlying tables by the system.
31. What is Locking ?
When two users simultaneously attempt to access the same data record, this is synchronised by a lock mechanism.When dialog transactions are programmed, locks are set and released by calling certain function modules. These function modules are generated automatically from the definition of so-called lock objects in the ABAP/4 Dictionary.To synchronize the access to a table by setting and removing locks, a Lock object has to be defined in the ABAP/4 Dictionary. Activating the lock object automatically creates function modules for setting and removing locks. These function modules must be included when programming interactive transactions.
32. What are the attributes of the data ?
What is the relationship existing between the various data elements ?
33. What is a Data Class?
The Data class determines in which tablespace the table is stored when it is created in the database.
33. What Are The Different Types Of Views In Sap?
In SAP, you have total four types of views. Based on the way in which the view is implemented and the methods that are permitted for accessing the view data they are divided into Database View, Projection View, Maintenance View and Help View.
Database views implement an Inner Join whereas Projection View, Maintenance View and Help View implement an Outer Join.
There are 4 Different types of Views in SAP. They are:
- Maintenance View
- Database View
- Projection View
- Help View
34. What Is A Data Class?
The Data class determines in which table space the table is stored when it is created in the database.
35. What Is The Difference Between Native Sql & Open Sql?
There are two types of SQL being used in SAP ABAP programming language. They are
Native SQL
Open SQL
Open SQL allows to access the database tables declared in the ABAP dictionary regardless of the database platform that the SAP R/3 system is using.
Native SQL allows to use database-specific SQL statements in a SAP ABAP program. This means that one can use database tables that are not administered by ABAP dictionary, and therefore integrate data that is not part of the SAP R/3 system.
Open SQL is not confined to any particular type of database while a Native SQL is confined to a particular type.
ABAP programs that uses only Open SQL statements will work in any R/3 system, regardless of the database system in use. Open SQL statements can only work with database tables that have been created in the ABAP dictionary.
36. What Are Conversion Routines ?
Non-standard conversions from display format to sap internal format and vice-versa are implemented with so called conversion routines.
Aggregated Objects Views, matchcodes, and lock objects are also called aggregate objects because they are formed from several related tables.
37. What Are The Differences Between Transparent Tables, Pooled Tables & Cluster Tables?
Differences between transparent, pooled and cluster tables are:
- Transparent tables have a one to one relationship with a physical table in an underlying database where as pooled tables and cluster tables have many to one relationship with a physical table in the underlying database (Relationship between tables in ABAP Dictionary & Underlying database).
For each transparent table there will be exactly only one table in the underlying database whereas many pooled tables are stored in a single table in an underlying database called table pool. Similarly many cluster tables are stored in a single table in the database called a table cluster
- In case of transparent tables, the underlying database table will have the same name, same number of fields and the fields will also have the same names as defined in ABAP Dictionary whereas for pooled tables and cluster tables the underlying database table will have different name, different number of fields and fields will have different names from what has been defined in ABAP Dictionary.
- Transparent tables can have one or more primary key Whereas Primary key of each pooled table of a table pool need not be same whereas Primary key of each cluster table of a table cluster should have at least one key in common.
- Secondary indexes can be created for transparent tables, but for pooled and cluster tables we cannot create any secondary index.
- Transparent tables can be accessed via both Native and Open SQL whereas pooled and cluster table can be accessed by Open SQL only.
Transparent tables are used to hold application data which includes both master data as well as transaction data.
Pooled tables reduce the amount of database resources needed when many small tables have to be opened at the same time.
Cluster tables are used when the tables have primary key in common and data in these tables are all accessed simultaneously.
38. What Functions Does A Data Dictionary Perform?
In a data management system, the principal functions performed by the data dictionary are:
- Management of data definitions
- Provision of information for evaluation
- Support for software development
- Support form documentation
- Ensuring that the data definitions are flexible and up-to-date.
39. What Is A Match Code?
Match Code is a tool to help us to search for data records in the system. Match codes are an efficient and user-friendly search aid where the key of a record is unknown.
40. What Are The Difference Between Tables And Structures?
Table:
- Table has an underlying database table
- Table has a primary key
- Table has technical attributes
Structure:
- No underlying database table
- No primary key
- No technical attributes
41. What Are The 3 Types Of Tables In Sap?
There are 3 types of tables in SAP Dictionary (DDIC). They are:
- Transparent Table
- Pooled Table
- Cluster Table
42. Can You Delete A Domain Which Is Being Used By Data Elements?
No
43. What Are Pooled Tables?
These are logical tables which must be assigned to a table pool when they are defined. Pooled tables can be used to store control data (such as screen sequences or program parameters).
44. What Are The Data Types Of The External Layer?
ACCP, CHAR, CLNT, CUKY,CURR, DATS, DEC, FLTP, INT1,INT2, INT4, LANG, LCHR,LRAW, NUMC, PREC, QUAN,RAW ,TIMS, UNIT, VARC.
45. What Are The Types Of Subroutines?
Internal Subroutines: The source code of the internal subroutines will be in the same ABAP/4 program as the calling procedure (internal call).
External Subroutines: The source code of the external subroutines will be in an ABAP/4 program other than the calling procedure.
46. What Is The Difference Between A Substructure And An Append Structure?
In the case of a substructure, the reference originates in the table itself, in the forma of a statement include.
In the case of an append structure, the table itself remains unchanged and the reference originates in the append structure.
47. What Is A Maintenance View?
Just like we have table maintenance (SM30) for each table, similarly if there is a requirement to maintain data for one or more tables in a single view, then maintenance view can be created. All the tables in a maintenance view must be linked with foreign key. The join conditions for maintenance views are always derived from the foreign key automatically and thus one cannot directly enter the join conditions as for database views. Unlike Database views, one can modify data from maintenance view.
Thus, a maintenance view allows you to maintain the data of an application object together.
48. What Is Locking ?
When two users simultaneously attempt to access the same data record, this is synchronised by a lock mechanism.
When dialog transactions are programmed, locks are set and released by calling certain function modules. These function modules are generated automatically from the definition of so-called lock objects in the ABAP/4 Dictionary. To synchronize the access to a table by setting and removing locks, a Lock object has to be defined in the ABAP/4 Dictionary. Activating the lock object automatically creates #function modules for setting and removing locks. These function modules must be included when programming interactive transactions.
Lock Mechanism : To set locks, a lock object must be defined in the ABAP/4 Dictionary. In this lock object, those tables in which data records are to be locked by calling a lock are determined. All tables included in a lock object must be connected to each other via foreign keys. The key fields of the tables in a lock object form the Lock arguments for the tables. The lock arguments are the basis for formulating the logical condition for identifying the records to be locked. When activating this lock object, two function modulesB with the namesENQUEUE_ and DEQUEUE_ are generated.
49. State The Differences Between Database View & Projection View?
The basic differences between projection view and database view are:
- Database view can built over many tables whereas projection view can be built over a single table only.
- Database view can be updated if the view is built over a single table whereas in projection view data can be updated.
- In case of database view, data updates can use open SQL or native SQL whereas in case of projection view, data updates must use open SQL.
- Database view can be buffered whereas Projection view cannot be buffered.
50. What Are The Relational Operations That Can Be Performed On View In Sap?
There are three operations that can be performed on views in SAP: Join, Projection and Selection.
- The Projection Operation is used to narrow a view’s focus to certain fields in a table.
- The Selection Operation is used to narrow a view’s focus to certain records in a table.
- The Join Operation is used to combine information from multiple tables into a single view.
51.What is the maximum number of match code Id’s that can be defined for one Match code object ?
A match code Id is a one character ID that can be a letter or a number.
52.Can we define our own Match Code ID’s for SAP Matchcodes ?
Yes, the numbers 0 to 9 are reserved for us to create our own Match Code IDs for a SAP defined Matchcode object.
53.What is an Update type with reference to a Match code ID?
If the data in one of the base tables of a matchcode ID changes, the matchcode data has to be updated. The update
type stipulates when the matchcode is to be updated and how it is to be done. The update type also specifies which
method is to be used for Building matchcodes . You must specify the update type when you define a matchcode ID.
54.Can matchcode object contain IDs with different update types ?
-Yes.
55.What are the update types possible ?
The following update types are possible:
Update type A: The matchcode data is updated asynchronously to database changes.
Update type S: The matchcode data is updated synchronously to database changes.
Update type P: The matchcode data is updated by the application program.
Update type I: Access to the matchcode data is managed using a database view.
Update type K: Access to the matchcode is achieved by calling a function module.
56.What are the two different ways of building a match code object ?
A match code can be built in two different ways :
·Logical structure : The matchcode data is set up temporarily at the moment when the match code is accessed.
(Update type I, K)
·Physical structure : The match code data is physically stored in a seperate table in the database. (Update type A,
S, P)
57.What are the differences between a Database index and a match code ?
·Match Code can contain fields from severeal tables whereas an index can contain fields from only one table.
·Match code objects can be built on transparent tables and pooled and cluster tables.
58.What is the function of a Domain?
·A domian describes the technical settings of a table field.
·A domain defines a value range, which sets the permissible data values for the fields, which refers to this
domain.
·A single domain can be used as basis for any number of fields that are identical in structure.
59.Can you delete a domain which is being used by data elements ?
-No.
60.What are conversion routines ?
Non standard conversions from display format to sap internal format and vice-versa are implemented with so called
conversion routines.
61.What is the function of a data element ?
A data element describes the role played by a domain in a technical context. A data element contains semantic
information.
62.Can a domain, assigned to a data element be changed ?
Yes. We can do so by just overwriting the entry in the field domain).
63.Can you delete data element which is being used by table fields .
No.
64.Can you define a field without a data element ?
Yes. If you want to specify no data element and therefore no domain for a field, you can enter data type and field length and a ashort text directly in the table maintenance.
65.What are null values ?
If the value of a field in a table is undefined or unknown, it is called a null value.
66.What is the difference between a structure and a table ?
Structures are constructed the almost the same way as tables, the only difference using that no database table is generated from them.
67.What is a View ?
A view is a logical view on one or more tables. A view on one or more tables i.e, the data from a view is not
actually physically stored instead being derived from one or more tables.
68.What is Repository Info. Systems ?
It is a tool with which you can make data stored in the ABAP/4 Dictionary available.
69.What is Locking ?
When two users simultaneously attempt to access the same data record, this is synchronised by a lock mechanism.
70.What is database utility ?
Database utility is the interface betweenn the ABAP/4 Dictionary and the underlying the SAP system.
71.What are the basic fucntions of Database utility ?
The basic functions of database utility are :
-Create database objects
-Delete database objects
-Adjust database objects to changed ABAP/4 dictionary definition.