Database - The Relational Model and Normalization - Discussion

Why not Determinants?

Definition: A determinant in a database table is any attribute that you can use to determine the values assigned to other attribute(s) in the same row.

Examples: Consider a table with the attributes employee_id, first_name, last_name and date_of_birth. In this case, the field employee_id determines the remaining three fields. The name fields do not determine the employee_id because the firm may have more than one employee with the same first and/or last name.

Similarly, the DOB field does not determine the employee_id or the name fields because more than one employee may share the same birthday.

A database key is a attribute utilized to sort and/or identify data in some manner. Each table has a primary key which uniquely identifies records. Foriegn keys are utilized to cross-reference data between relational tables.

Key can be a single attribute as well as a combination of multiple attribute but must contain unique value & must not be null. A primary key with multiple attribute is known as composite primary key.

A primary key with multiple attribute know as composite key.

Then what are determinants?

Right! I agree @Anand.