A foreign key is a field in a relational table that matches the primary key column of another table. In a foreign key relationship, the child object has a foreign key column and the parent object has a primary key column. The MDM Hub uses the keys to associate a parent record with a child record. The foreign key column of the child record contains the value of the associate parent primary key.

The following image shows a Phone child object linked to a Person parent object by a foreign key relationship:

The Person object has a primary key column called ROWID_OBJECT and the Phone object has a foreign key column called Person_ID. The primary key value of 3 links the record for Tom to the record for the phone number 555-3333.

The constraint attribute requires the following syntax:

<
child base object name>(<
foreign key column name>).<
parent base object name>(<z
primary key column name>)

The following code shows the constraint attribute for the example:

constraint="C_PHONE(PERSON_ID).C_PERSON(ROWID_OBJECT)"