ABAP Data Dictionary Tutorial SE11: Table, Lock Object, View & Structure

Details: Last Updated: 03 July 2017

What is Data Dictionary?

Data Dictionary is a central source of information for the data in a information management system. Its main function is to support the creation and management of data definitions (or "metadata").

ABAP Dictionary 3 levels

Objects in the ABAP Dictionary resided on three levels that support their re-usability. These levels are:

Tables and structures
Data elements
Domains

Lets look into them in detail -

Domains

Describes the technical characteristics of a table field
Specifies a value range which describes allowed data values for the fields
Fields referring to the same domain (via the data elements assigned to them) are changed when a change is made to the domain
Ensures consistency

Ex. Purchasing document number (EBELN)

Data Elements

Describes the role played by a field in a technical context
Fields of same semantic meaning can refer to the same data element
Contains the field information

Ex. Purchasing document number (EBELN)

Tables

Represent the Database Tables where data actually resides.
Tables can be defined independently of the database in the ABAP Dictionary.
The fields of the table are defined with their (database-independent) SAP ABAP data types and lengths.

Structures

Are record declarations that do NOT correspond to a Database Table.
Just like user-defined data type.
Defined like a table and can then be addressed from ABAP programs.
Structures contain data only during the runtime of a program.

Aggregated Objects of ABAP Dictionary

Aggregated means consisting of several components. In the ABAP Dictionary, aggregated objects are objects which come from several different transparent tables.

Views
Search Help
Lock Objects

Lets look into them in detail

Views

Views in SAP _ ABAP are used to summarize data which is distributed among several tables
The data of a view is not actually physically stored. The data of a view is instead derived from one or more other tables
It is tailored to the needs of a specific application

Search Help

A Search help is a tool to help you search for data records in the system
An efficient and user-friendly search assists users where the key of a record is unknown

Lock Objects

Simultaneous accessing of the same data record by two users in the SAP system is synchronized by a lock mechanism.
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

Function modules : Enqueue_<obj name> - to lock the table dequeue_<obj name> - to release the lock