SAP ABAP Tables Interview Questions

What is a table pool?
What is a table pool in SAP?

A table pool (or pool) is used to combine several logical tables in the ABAP/4 Dictionary. The pool definition consists of at least two keys fields and a long argument field (VARDATA).

What are pooled tables?

The logical tables that are assigned to a table pool when they are defined are called as pooled tables. Pooled tables used to store control data such as screen sequences or program parameters.

What do you understand by pool tables?

The tables that are having a many to one relation are termed as pool tables.

Give an example where pool tables are stored.

Database levels are examples of where pool tables are stored.

What do you understand by transparent tables?

The tables that are having a one to one relation are known as transparent tables.

What are null values?

If the field value in a table is undefined or unknown, it is called a null value.

What is use of transparent table in ABAP? How it is different from Pool tables?
Explain the difference between pool tables and transparent tables?
Differentiate between transparent and pool tables.
Do you know the difference between pool tables and transparent tables?
What is the difference between pooled tables and transparent tables?

The pool tables have many to one relationship with the tables in database. These tables are stored at the database level.
The transparent tables have one to one relationship with the tables in database. Structure of these tables correspond to single database fields.

What is a foreign key relationship?
Explain Foreign key relationship?
What is the meaning of foreign key relationship?

The relationship established between the tables should be defined clearly at field level. Data entered should be verified against the existing data to ensure that there is no contradiction. Foreign keys are used to ensure the data consistency.

What is the use of foreign key relationship?

Data consistency.

In ABAP what are the differences between table and structure in data dictionary?
Differentiate between Structure and table in the data dictionary of ABAP.

The difference between table and structure are -

TABLE	STRUCTURE
Table can store data physically.	Structure can't store data physically.
Table can include primary key.	Structure can't include primary key.
Table can include technical attribute.	Structure can't have a technical attribute.

What is a table cluster?

A table cluster combines several logical tables in the ABAP/4 Dictionary. The rows from different tables within the cluster are brought together into a single physical record. The records from the cluster tables are thus stored in a single table in the database that is assigned to a cluster.

How to create 'table cluster'?
How can cluster table be created?

Go to SE11 transaction. It opens ABAP Dictionary: Initial Screen.
Select Database table radio button and enter the table name. Click on "Create" button.
It opens Dictionary: Change Table screen. Enter the Short Description, Delivery class and desired Data Browser/Table View Maint. Select desired Data Browser/Table View Maint value from the drop down.
Open Fields tab to enter the table fields information. To specify the field is of specific custom data element type, the data elements should be predefined or created.
Press "(Ctrl + S)" or "Save" icon to save the Table definition.
Now choose menu path “EXTRAS -> Change” to change table category.
A dialogue box appears with the table type options. Select the table type as 'Pooled table' or 'Cluster table'.
After selecting the table, return to the field maintenance screen for the table. Field pool or cluster name is displayed on the Attributes tab page in addition to the standard fields.
Enter the name of the table cluster or table pool to which we want to assign the cluster table.

Can we add include structure in standard table or structure?

Yes.

Explain the difference between Template and Table?
Differentiate between Table and Template?
What is the difference between Table and Template?

The difference between the table and template is -

table is a dynamic.
template is a static.

What is table buffer? Which type of tables used this buffer?
What is the meaning of table buffer? This buffer is used by which type of table?
What do you understand by the term table buffer?

Generally, in technical terms, buffer represents additional memory area. Table buffer means the additional memory area that is available on the application server for the table. When we call data from database table, it loads from application server. Transparent tables and pool tables are buffered, while cluster table cannot be buffered.

How data is stored in cluster table?

Cluster table stores the data as name value pair. A cluster table contains data from multiple DDIC tables.

What is the different between template and a table?

We can define table as dynamic and template as static.

Explain the difference between cluster tables and Pool table?

The data of several cluster tables is stored together in a single table cluster in the database. A cluster table known only in the ABAP Dictionary, not in the database.
The data of several pooled tables are stored together as a table pool in the database.

To create a transparent table, which data dictionary object is selected?

What is the use of breakpoints table in ABAP programming?

Breakpoint table used to review the breakpoints when a large program with many break points set. It allows to review the breakpoints and allows for the removal of breakpoints that are no longer required.

How can the standard tables of SAP be modified?
State the two methods needed to modify the standard tables of SAP.

The standard table of SAP can be modified mainly by two methods -

Customizing includes
Append structures

What is the maximum number of structures that can be included in a table or structure?

Nine.

What Is the Difference Between Free and Refresh?
Can you highlight the differences between Free and Refresh?

Refresh clears the internal table data; at the same time, it releases dynamically allocated memory. Predefined memory not released. Refresh is mainly involved with the body of the table.
Free clears the internal table data, at the same time releases both predefined and dynamically allocated memory. Internal table structure will not available anymore. Free is mainly used to retrieve the memory space of a table.

What happens when a Table is activated in Data dictionary?

When the table is activated, a physical table definition is created in the database for the table definition stored in the ABAP dictionary. It is available for any insertion, modification and updating of records by any user.

What is a Size Category?

The Size category describes the possible space requirement for the table in the database.

How many types of size categories and data classes are there?

There are five size categories (0-4) and 11 data classes and 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 frequently)
APPL2 – Organizational data (customizing data that is entered when system is Configured and then rarely changed)

The other two types are -

USR
USR1 – Intended for customers own developments

What are control tables?

Control tables perform the following -

Specified values for the size category.
Data class are mapped to database-specific values.

In the ABAP/4 Dictionary Tables can be defined independent of the underlying database (T/F)?

True

ABAP/4 Dictionary contains the _ (Logical/Physical) definition of the table.

Logical

How many tables can an append structure be assigned?

Only One. Append structure cannot be reusable. We cannot use it for multiple tables.

If a table that is to be extended contains a long field, we cannot use append structures. Why?

No append structures can be added to tables with long fields (data types VARC, LCHR or LRAW). This is because a long field must always be the last field in the table. However, structures with long fields can be enhanced with append structures.

Can we include customizing include or an append structure with Pooled or Cluster tables?

What is the difference between a structure and a table?

The difference between table and structure are -

TABLE	STRUCTURE
Table can store data physically.	Structure can't store data physically.
Table can include primary key.	Structure can't include primary key.
Table can include technical attribute.	Structure can't have a technical attribute.

What is the process of creating a table in the data dictionary?

The first thing that we should do is create domains. Next, we should begin with creating data elements like properties. The last step is to create the tables.

Can you tell the different components of the selection table?

Sign, low, high, and options are the different components of the selection table.

Tell us about the methods to modify SAP standard tables?

Customizing includes and append structures are the two different methods used to modify SAP standard tables.

List the different types of data classes.

A data class is a class that contains only fields and crude methods for accessing other classes. Data classes are classified into four types depending on the type of data they contain -

Master Data: Data change very rarely.
Transaction Data: Data changes are depending on requirements.
Organization Data: Data is a customized and entered to the system when the system is configured. It is rarely changed.
System Data: Data is used by the SAP R/3 system.

What do you understand by the term dispatcher?

SAP dispatcher is a control agent that manages resources for the R/3 applications.

How do you read data from database table in SAP ABAP?

The only way to read data from database table in SAP ABAP is using select (open SQL) statements.

Buffering concept usage in SAP Tables?

There are three type of buffer

Single record
Generic buffer
Full buffer

Buffering is use for improving performance. It improves performance 10 to 100 times more.

A field containing currency amounts (data type CURR) must be assigned to a reference table and a reference field. Explain?

A system table as a reference table contains all the valid currencies assigned or contains a field with the currency key format from any other table. This field is called as reference field. The field assignment value contains currency amounts to the reference the field and the assignment is made at runtime. The value in the reference field determines the currency of the amount.

A field containing quantity amounts (data type QUAN) must be assigned to a reference table and a reference field. Explain?

A system table as a reference table contains all the valid quantity assigned or contains a field with the quantity key format from any other table. This field is called as reference field. The field assignment value contains quantity amounts to the reference the field and the assignment is made at runtime. The value in the reference field determines the quantity of the amount.

What is the significance of Technical settings (specified while creating a table in the data dictionary)?

We can control how database tables are created in the database by specifying technical settings. The technical settings allow to

Optimize storage space requirements
Optimize table access behavior
Specify the buffering
Log the changes to entries