What can be a primary key?

What can be used as a primary key?

Often, a unique identification number, such as an ID number or a serial number or code, serves as a primary key in a table. For example, you might have a Customers table where each customer has a unique customer ID number. The customer ID field is the primary key.

What are the 5 types of primary key?

Primary Key.Candidate Key.Alternate Key.Super Key.Composite Key.Foreign Key.Unique Key.

Can there be 3 primary keys?

A table can only ever have a one primary key. It is not possible to create a table with two different primary keys. You can create a table with two different unique indexes (which are much like a primary key) but only one primary key can exist.

What is primary key what are its types?

Primary Key A primary key is a column of a table or a set of columns that helps to identify every record present in that table uniquely. There can be only one primary Key in a table. Also, the primary Key cannot have the same values repeating for any row.