Referential integrity between tables is enforced by default when you create a relationship in your database diagram. An enforced relationship ensures each value entered in a foreign key column matches an existing value in the related primary key column.
You can change the conditions under which referential integrity is enforced by editing the relationship’s properties.
To change referential integrity options for a new relationship
For information about the options available for SQL Server databases, see Database Designer Considerations for SQL Server Databases. For more information about the options available for Oracle databases, see Database Designer Considerations for Oracle Databases.
To change referential integrity options for an existing relationship
For information about the options available for SQL Server databases, Database Designer Considerations for SQL Server Databases. For more information about the options available for Oracle databases, see Database Designer Considerations for Oracle Databases.
The relationship is updated in the database when you save the diagram or either of the related tables.