Define Constraints for the Existence of Joins

You must ensure that Oracle Database knows about the joins between the dimension tables and the fact tables.

See your Oracle Database documentation.

To do so, you create constraints in SQL*Plus or the Oracle Enterprise Manager Database Control. In the Oracle Enterprise Manager Database Control, you select the table on which you must create a constraint, then select the Constraint tab.

You create a different type of constraint for each kind of table, as follows:

• For dimension tables, create a UNIQUE key constraint.

• For fact tables, create a FOREIGN key constraint and specify the referenced schema and referenced table. In the Constraint Definition area, include the foreign key columns in the fact table and the corresponding unique keys in the dimension table. An attempt to create a foreign key on a fact table can fail if the foreign key column data doesn't match the unique key column data on the dimension table.