Table: FOREIGN KEY Constraint

Use this page to optionally create or edit a FOREIGN KEY constraint.

A foreign key constraint designates one or more table columns whose values relate to values in a unique or primary key column. The value of the foreign key must appear as a primary key value in one of the table's rows.

For example, the SCOTT.EMP table could contain a DEPTNO foreign key column that is related to a DEPTNO primary key in the SCOTT.DEPT table.

When creating a table, you cannot create a foreign key constraint that refers to a foreign key within the table you are creating. If you want to create this kind of recursive relationship, you must first create the table, and then edit it to add the foreign key constraint.

Field Descriptions

New Constraints

Field	Description
Constraint Name	Enter the name that will identify the constraint.
Cascade Delete	Select to delete all table rows dependant on the primary key when a row containing the primary key is deleted. For example, you could delete a row containing 10 as the value of the primary key DEPTNO in the SCOTT.DEPT table. All dependent rows in the SCOTT.EMP table that contain DEPTNO equal to 10 would also be deleted when the row in SCOTT.DEPT is deleted.
Foreign Table	Choose a table that contains one or more primary keys on which to base your FOREIGN KEY constraint.
Retrieve Keys	Click to populate the Retrieved Keys list with the primary key or foreign keys in the Foreign Table.

Retrieved Keys List

Field	Description
Columns	Displays columns containing a primary or foreign key.
Keys	Displays whether the column is a primary or foreign key.
More	Click to add more keys.
Add to List	Click to create a foreign key constraint. The new constraint will be added to the Existing Constraints list below.

Existing Constraints

Field	Description
Name	Displays the name of an existing constraint. Click if you want to delete the constraint. The deletion will be permanent. Clicking Cancel will not undo it.
Selected Columns	Displays the column(s) on which the constraint is based.
Enable/Disable	Select to cause the Oracle database to enforce the constraint when its conditions are met. Deselect to disable the constraint.

Field

Description

Name

Displays the name of an existing constraint.

Click if you want to delete the constraint. The deletion will be permanent. Clicking Cancel will not undo it.

Selected Columns

Displays the column(s) on which the constraint is based.

Enable/Disable

Select to cause the Oracle database to enforce the constraint when its conditions are met. Deselect to disable the constraint.

Additional Information

On Portal Center:

For more information go to the documentation section of Portal Center.

Locating this Page

To locate this page in OracleAS Portal:

On the Portal Builder page, click the Navigator link.
Click the Database Objects tab.
In the Name column, scroll down to the schema in which you want to build the object.
Click the schema's name.
Click Create New...Table.
Complete each wizard page until you reach this page.