A primary key is the column or columns that contain values that uniquely identify each row in a table. A database table must have a primary key for Optim to insert, update, restore, or delete data from a database table. Optim uses primary keys that are defined to the database.
Option D. Sr. No.
Where is the primary key?
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.
What is primary key and foreign key?
A primary key is used to assure the value in the particular column is unique. The foreign key provides the link between the two tables.
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