The rules for defining foreign keys are similar in Microsoft® Access and Microsoft SQL Server™. The number of columns and data types of each column specified in the foreign key clause must match the references clause. A nonnull value entered in this column(s) must exist in the table and column(s) defined in the references clause, and the referenced table’s columns must have a PRIMARY KEY or UNIQUE constraint.
The Access cascading updates and deletes are not available with SQL Server. This option is used in situations where both the parent and child values are deleted when a parent row is deleted. In SQL Server, this option must be enforced with table triggers. For more information, see Nested Triggers.