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This is documentation for Caché & Ensemble. See the InterSystems IRIS version of this content.

For information on migrating to InterSystems IRIS, see Why Migrate to InterSystems IRIS?

Property Definitions

Describes the structure of a property definition. Note that a relationship is a property.


A property contains information relevant to an instance of a class. You can add property definitions to object classes. They are not meaningful in other kinds of classes.


A property definition has the following structure:

/// description Property name As classname (parameter_list) [ keyword_list ] ;

Or (for a list property):

/// description Property name As List Of classname (parameter_list) [ keyword_list ] ;

Or (for an array property):

/// description Property name As Array Of classname (parameter_list) [ keyword_list ] ;

Or (for a relationship property):

Relationship name As classname [ keyword_list ] ;


  • description (optional) is intended for display in the Class Reference. The description is blank by default. See “Creating Class Documentation” in Using Caché Objects.

  • name (required) is the name of the property. This must be a valid class member name, and must not conflict with any other class member names.

  • classname (optional) is the name of the class on which this property is based.

  • parameter_list (optional) is a comma-separated list of parameters and their values. If specified, these should be either parameters used by classname or parameters that are available to all properties.

    If this list is omitted, also omit the parentheses.

  • keyword_list (required for a relationship property but otherwise optional ) is a comma-separated list of keywords that further define the property.

    See the section “Property Keywords.”

    If this list is omitted, also omit the square brackets.


/// Person's Social Security number. 
Property SSN As %String(PATTERN = "3N1""-""2N1""-""4N") [ Required  ]; 

See Also