Using Caché Objects - InterSystems Documentation

Relationship Basics
the relationship Invoice.Items has cardinality of CHILDREN because Items is a collection of
children from the point of view of Invoice. LineItem.TheInvoice has cardinality of PARENT
because TheInvoice refers to the parent of this LineItem.
The cardinality value of a relationship must correspond to the cardinality value of the inverse
relationship as defined in the following table:
ONE
MANY
PARENT
CHILDREN
MANY
ONE
CHILDREN
PARENT
14.1.2 Defining a Relationship
To create a relationship, there are a pair of complementary relationship properties. In the
Caché Studio you can define a relationship property using the New Property Wizard and
checking the Relationship option. See the Relationships section of the Studio documentation
for details.
When you define a relationship property, Studio automatically creates the inverse relationship
property in the associated class.
You can also define a relationship property directly in Studio. The syntax is:
Relationship Name As Type
[Inverse = related_class,
Cardinality = cardinality_type
where
• “TYPE” , “INVERSE” and “CARDINALITY” are required.
• related_class specifies the other half of the relationship and must be a persistent class.
• cardinality_type, the value of cardinality, indicates the complementary cardinality of
related_class (and can have a value of ONE, MANY, PARENT, or CHILDREN).
For example, here are the definitions of two related classes, Company and Employee. Company
is:
Using Caché Objects 127