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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?


Specifies the cardinality of this relationship property. Required for relationship properties. Not used for other properties.


To specify the cardinality of a relationship property, use the following syntax:

Relationship relname As classname [ Cardinality = cardinality; inverse = inverse ];

Where cardinality is one of the following:

  • one

  • many

  • parent

  • children


This keyword specifies the cardinality of a relationship property.

The Cardinality keyword is required for relationship properties. It is ignored by non-relationship properties.

For more information on relationships, see “Defining and Using Relationships” in Using Caché Objects.


There is no default. When you define a relationship, you must specify the Cardinality keyword.


Relationship Chapters As Chapter [ Cardinality = many; inverse = Book ];

See Also