History, asked by Amansinghk, 1 year ago

what is primary key?

sreejukta: A primary key, also called a primarykeyword, is a key in a relational database that is unique for each record. It is a unique identifier, such as a driver license number, telephone number (including area code), or vehicle identification number (VIN). A relational database must always have one and only one primary key.

Answers

Answered by JashanBhardwaj

In Ms-Excel, primary key is a field or set of fields with values that are unique throughout a table

dharamjatt: A primary key is a special relational database table column (or combination of columns) designated to uniquely identify all table records. A primary key's main features are: It must contain a unique value for each row of data. It cannot contain null values.

Answered by siddhartharao77

Following are the details about primary key:

1. It is a type of constraint.

2. It is used to uniquely identify each row in a table.

3. A primary key cannot contain a null value.

4. A table can have only one primary key.If above 1 it is called as a composite key.

Hope this helps!

Previous Question

Next Question