| | DMA Containment Model (Site not responding. Last check: 2007-10-13) |
 | | The relationship between a container and a contained object is modeled explicitly in DMA with the introduction of a third object, the ContainmentRelationship object, and its subclasses DirectContainmentRelationship and ReferentialContainmentRelationship. |
 | | However, direct containment is a one-to-many relationship (each child object has only one parent, while a parent can have many children), so it is possible to express direct containment via a property on the child object which directly references the parent, rather than going through an intermediate relationship object. |
 | | When an RDBMS is used for this purpose, then for N:M relationships a natural way to model the data relationships in the database schema is to have a table where the rows of the relationship are stored, and to perform a join between tables as illustrated in the sample code in the appendix. |
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