Foreign Key Constraints

Visual Database Tools

Visual Database Tools

Foreign Key Constraints

A foreign key constraint works in conjunction with primary key or unique constraints to enforce referential integrity among specified tables. For example, you can place a foreign key constraint on the title_id column in the publishers table to ensure that a value entered in that column matches an existing value in the title_id column of the titles table.

In database diagrams, a foreign key constraint is automatically placed on specified columns when you create a relationship to a table from another table to which a primary key or unique constraint is attached. For more information about creating relationships, see Creating a Relationship Between Tables.

To See
See which columns participate in the foreign key side of a relationship Viewing Foreign Key Attributes
Change which columns are related to columns in the primary key table Modifying a Foreign Key
Check existing data when creating a relationship Checking Existing Data when Creating a Relationship
Disable a foreign key constraint during INSERT and UPDATE transactions Disabling a Foreign Key Constraint with INSERT and UPDATE Statements
Disable a foreign key constraint during replication of the table Disabling a Foreign Key Constraint for Replication
Remove the requirement to enforce referential integrity between primary key columns and the related columns in another table Deleting a Foreign Key Constraint