ABAP Dictionary
Data definitions (metadata) are created and managed in the ABAP Dictionary. The ABAP Dictionary permits a central description of all the data used in the system without redundancies. New or modified information is automatically provided for all the system components. This ensures data integrity, data consistency and data security.
You can create the corresponding objects (tables or views) in the underlying relational database using these data definitions. The ABAP Dictionary therefore describes the logical structure of the objects used in application development and shows how they are mapped to the underlying relational database in tables or views.
The ABAP Dictionary also provides standard functions for editing fields on the screen, for example for assigning a screen field an input help.
What Information is Stored in the ABAP Dictionary?
The most important object types in the ABAP Dictionary are tables, views, types, domains, search helps and lock objects.
Tables are defined in the ABAP Dictionary independently of the database. A table having the same structure is then created from this table definition in the underlying database.
Views are logical views on more than one table. The structure of the view is defined in the ABAP Dictionary. A view on the database can then be created from this structure.
Types are used in ABAP programs. The structure of a type can be defined globally in ABAP programs. Changes to a type automatically take effect in all the programs using the type.
Lock Objects are used to synchronize access to the same data by more than one user. Function modules that can be used in application programs are generated from the definition of a lock object in the ABAP Dictionary.
Domain
A domain defines a value range. A domain is assigned to a data element. All table fields or structure components that use this data element then have the value range defined by the domain. The relationship between the field or component and the domain is thus defined by the data element of the field or component.
Fields or components that refer to the same domain (with the assigned data elements) are also changed when the domain is changed. This ensures that the value ranges of these fields or components are consistent. Fields or components that are technically the same can thus be combined with a reference to the same domain.
The value range of a domain is defined by specifying a data type and length (and number of decimal places for numeric data types).
A personnel number is defined by the data format NUMC and by specifying the number of places for this personnel number. The value range of a domain can be restricted by definin fixed length. If all the fields or components that refer to the domain should be checked against a certain table, this table can be defined as the value table of the domain.
Output attributes can also be defined for all the fields or components that refer to the domain A conversion routine can be assigned to a domain. This conversion routine converts values from display format to internal format for the fields or components that refer to this domain.
Data definitions (metadata) are created and managed in the ABAP Dictionary. The ABAP Dictionary permits a central description of all the data used in the system without redundancies. New or modified information is automatically provided for all the system components. This ensures data integrity, data consistency and data security.
You can create the corresponding objects (tables or views) in the underlying relational database using these data definitions. The ABAP Dictionary therefore describes the logical structure of the objects used in application development and shows how they are mapped to the underlying relational database in tables or views.
The ABAP Dictionary also provides standard functions for editing fields on the screen, for example for assigning a screen field an input help.
What Information is Stored in the ABAP Dictionary?
The most important object types in the ABAP Dictionary are tables, views, types, domains, search helps and lock objects.
Tables are defined in the ABAP Dictionary independently of the database. A table having the same structure is then created from this table definition in the underlying database.
Views are logical views on more than one table. The structure of the view is defined in the ABAP Dictionary. A view on the database can then be created from this structure.
Types are used in ABAP programs. The structure of a type can be defined globally in ABAP programs. Changes to a type automatically take effect in all the programs using the type.
Lock Objects are used to synchronize access to the same data by more than one user. Function modules that can be used in application programs are generated from the definition of a lock object in the ABAP Dictionary.
Domain
A domain defines a value range. A domain is assigned to a data element. All table fields or structure components that use this data element then have the value range defined by the domain. The relationship between the field or component and the domain is thus defined by the data element of the field or component.
Fields or components that refer to the same domain (with the assigned data elements) are also changed when the domain is changed. This ensures that the value ranges of these fields or components are consistent. Fields or components that are technically the same can thus be combined with a reference to the same domain.
The value range of a domain is defined by specifying a data type and length (and number of decimal places for numeric data types).
A personnel number is defined by the data format NUMC and by specifying the number of places for this personnel number. The value range of a domain can be restricted by definin fixed length. If all the fields or components that refer to the domain should be checked against a certain table, this table can be defined as the value table of the domain.
Output attributes can also be defined for all the fields or components that refer to the domain A conversion routine can be assigned to a domain. This conversion routine converts values from display format to internal format for the fields or components that refer to this domain.
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