What is a composite key?

74.

a primary key and foreign key in a table composed together

two foreign keys of two tables composed together

a primary key composed of multiple columns in a table creating a unique key

All of the above

none of the above

A key made of two or more columns is known as composite key. Composite key shows how columns in a table relate to each other. when there is no unique value in a table a unique value is created combining two columns,thus creating a unique combination which works as primary key.