How many primary keys are there?

Question

Primary keys must contain UNIQUE values, and cannot contain NULL values. A table can have only ONE primary key; and in the table, this primary key can consist of single or multiple columns (fields).

Can there be 3 primary keys?

No, we can't. A table can have only one Primary Key. The Primary Key can be defined on a single column or more than one columns. If the Primary Key is defined using more that one column, it is known as a Composite Key (or Composite Primary Key).

Can we have 2 primary keys in a table?

A primary key is a field or set of fields with values that are unique throughout a table. Values of the key can be used to refer to entire records, because each record has a different value for the key. Each table can only have one primary key.

Expert · Answer

No, we can't. A table can have only one Primary Key. The Primary Key can be defined on a single column or more than one columns. If the Primary Key is defined using more that one column, it is known as a Composite Key (or Composite Primary Key).

Expert · Answer

A primary key is a field or set of fields with values that are unique throughout a table. Values of the key can be used to refer to entire records, because each record has a different value for the key. Each table can only have one primary key.

How many primary keys are there?

Can there be 3 primary keys?

Can we have 2 primary keys in a table?

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