Language Reference Guide > Language Reference Guide > System Classes > ValueDefinition Class > Keyword Attribute
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Keyword Attribute
Data Type: varchar(256)
4GL Access: RW
This attribute specifies the keyword used to identify this set of values. Keywords must be prefixed by "TVS_", and be valid Ingres names.
There are two special-case keywords used in tag definitions: TVS_VALUE and TVS_NA. Neither has a corresponding value definition.
TVS_NA
Signifies that no default value or valuelist is appropriate for the particular tag, attribute, or field
TVS_VALUE
Defines an ad hoc value definition—that is, a value definition without a corresponding keyword. This is essential for the "values" tag, which defines allowedvalues for attributes and fields (as opposed to allowedvalues for tags). Without this, there would be huge numbers of hard-coded TVS definitions.
This keyword has its own syntax:
TVS_VALUE(keyword: expression)
where keyword and expression are defined precisely as in the Definition Attribute.
This preserves the rule that all tag definitions have TVS values and enables business data lookup and validation to exploit the built-in TVS processing provided by ValueDefinitionProxy.ListTextValues() (see ListTextValues Method).
Last modified date: 06/25/2024