WHERE

Customizing the metamodel > Keywords for USRPROPS > WHERE

WHERE

WHERE displays only those definitions in the Choices dialog that contain a fixed value in a named property of the definition.

Syntax

[ ... ]

Indicates that ... is optional.

a | b

Indicates that keyword a or b is acceptable but there must be one or the other.

identifier*

Indicates that the expression represented by the identifier can appear multiple times.

WHERE where_clause*

where_clause: "property name" = | < | <= | > | >= | <> | != "value" [ AND | OR where_clause*]

Also valid:

( "property name" = | < | <= | > | >= | <> | != "value" [ AND | OR where_clause*] )

Example

Rename Definition "User 1" To "Aircraft Type"
Rename Definition "User 2" To "Filtered Aircraft"
List "Engine"
{ Value "Propeller"
Value "Jet"
Value "Glider"
}
Definition "Aircraft Type"
{ Property "Engine Type"
{ EDIT Text List "Engine" Length 48 }
}
Definition "Filtered Aircraft"
{ Property "Selected Aircraft Type"
{ edit listof "Aircraft Type" WHERE "Engine Type" = "Jet"}
}

If this example was applied to an encyclopedia, and the following Aircraft Type definitions were created in the encyclopedia:

Mustang (engine = Propeller) Spitfire (engine = Propeller) F-16 Fighting Falcon (engine = Jet) F-86 Sabre (engine = Jet)

then when you create a definition of type Filtered Aircraft (named Current Jet Fighters, for example), clicking Choices reveals only two choices: F-16 Fighting Falcon and F-86 Sabre; all definitions with Engine Type set to Propeller do not appear in the list.