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 have the value range defined by the domain. The relationship between the field or component and the domain is defined by the data element of the field or component.
When you change the domain, the system automatically changes fields or components that refer to this domain (with the assigned data elements). This ensures that the value ranges of these fields or components are consistent. Fields or components that are technically the same can be combined with a reference to the same domain. In the following figure you can see an example where fields from different tables refer to a 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 defining fixed values . If all the fields or components that refer to the domain must be checked against a certain table, you can define this table as the value table of the domain.
You can also define output attributes for all the fields or components that refer to the domain. For more information, see Creating Domains . 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.