What are the primary keys?

Question

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.

What is a primary key example?

A primary key is a column -- or a group of columns -- in a table that uniquely identifies the rows of data in that table. For example, in the table below, CustomerNo, which displays the ID number assigned to different customers, 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.

What are the types of primary key?

Primary Key. The primary key refers to a column or a set of columns of a table that helps us identify all the records uniquely present in that table. ... Super Key. ... Candidate Key. ... Alternate Key. ... Foreign Key. ... Composite Key. ... Unique Key.

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.

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