Can a compound key be a primary key?

Can a compound be a primary key?

A compound primary key is made up of multiple fields and follows the requirements described in Primary Keys in Entities. To use a compound primary key, you must create a wrapper class. In order, two entities use compound primary keys: Part and LineItem .

Are all composite keys primary keys?

A Composite key is a Candidate key or Primary key that consists of more than one attribute. Sometimes it is possible that no single attribute will have the property to uniquely identify tuples in a table. In such cases, we can use a group of attributes to guarantee uniqueness.

What Cannot be a primary key?

Primary keys must contain unique values. A primary key column cannot have NULL values. A table can have only one primary key, which may consist of single or multiple fields.

How do you make a compound primary key?

To select more than one field to create a composite key, hold down CTRL and then click the row selector for each field. On the Design tab, in the Tools group, click Primary Key. A key indicator is added to the left of the field or fields that you specify as the primary key.