In this video, I have provided the explanation to an interview question. I hope it will be helpful. You can watch and provide your feedback
Answer: There are mainly three types of tables and three types of Structures in SAP. I have provided the details of those tables and structures along with examples in this document.
There is a physical table on the database for each transparent table. The names of the physical tables and the logical table definition in the ABAP/4 Dictionary correspond.
All business data and application data are stored in transparent tables.
Ex: Purchase Order Header Data- EKKO
2. Pooled Table:
Pooled tables can be used to store control data (e.g. screen sequences, program parameters or temporary data). Several pooled tables can be combined to form a table pool. The table pool corresponds to a physical table on the database in which all the records of the allocated pooled tables are stored. This is for internal purposes, such as storing control data or update texts etc.
Ex: Material Info Record (Plant-Specific)- A017
3. Cluster Table:
Cluster tables contain continuous text, for example, documentation. Several cluster tables can be combined to form a table cluster. Several logical lines of different tables are combined to form a physical record in this table type. This permits object-by-object storage or object-by-object access. To combine tables in clusters, at least parts of the keys must agree. Several cluster tables are stored in one corresponding table on the database. This is for internal purposes, such as storing control data or update texts etc.
Ex: Accounting Document Segment- BSEG
A structure (structured type) consists of components (fields) whose types are defined. A component can have an elementary type, a structured type, a table type or reference type
Structures are used specially to define the data at the interface of module pools and screens and to define the types of function module parameters.
Structures that are used more than once can be changed centrally because they were defined centrally. The active ABAP Dictionary makes this change at all relevant locations. ABAP programs or screen templates that use a structure are automatically adjusted when the structure changes.
Ex: MEPO1220- Fields for Screen 9101
5. Append Structure:
An append structure defines a set of fields that belong to another table or structure but are treated in the correction management as a separate object.
Append structures are used to support modifications.
Ex: ISAUTOLAB- IS AUTOMOTIVE Enhancements in EKPO
6. Generated view Structure:
In activation a structure is generated for a view. This structure serves as interface for the runtime environment. It does not generally appear in the ABAP/4 Dictionary. This is for internal purposes, such as storing control data or update texts etc.
Ex: V_T438M_B- Direct Procurement
We can see the type of table or structure by displaying the details with SE11 T Code for a single entry and for multiple tables or structures, we can get from table SAP Tables-DD02L. Both the methods are explained below
1.Through SE11 Transaction Code:
Input Screen: Input the Table which you want to check and click on display icon as shown below
Output Screen: The table or structure type will be visible as shown in the highlighted box
2. Through Table DD02L: This method will be helpful to know the table types of many tables
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