Primary and Surrogate Keys

Learn about keys in PostgreSQL.

Primary key

Primary keys are a database constraint allowing us to implement the first and second normal forms. The first rule to follow to reach the 1NF says, “there are no duplicated rows in the table.”

A primary key ensures two things:

  • The attributes that are part of the primary key constraint definition are not allowed to be null.

  • The attributes that are part of the primary key are unique in the table’s content.

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