What is primary key and secondary key?

Question

A primary key is the field in a database that is the primary key used to uniquely identify a record in a database. A secondary key is an additional key, or alternate key, which can be use in addition to the primary key to locate specific data.

What is primary key and example?

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

What is a secondary key example?

Let's say you selected Student_ID as primary key, therefore Student_Enroll and Student_Email will be Secondary Key (candidates of primary key).

What is a primary key key?

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.

Is foreign key a secondary key?

Foreign key is an attribute which is a Primary key in its parent table but is included as an attribute in the host table. Foreign keys may accept non-unique and null values.

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