Why do we use primary keys for foreign keys?

Question

Essentially, primary and foreign keys are used as a way to constrain or link related data in a database. This ensures that data remains consistent and that the database contains no redundant data. For example, if you delete a table (or even a row in a table) that other tables rely on, the redundant data is removed. 25 июл. 2012 г.

Do you need a primary key if you have a foreign key?

Primary keys always need to be unique, foreign keys need to allow non-unique values if the table is a one-to-many relationship. It is perfectly fine to use a foreign key as the primary key if the table is connected by a one-to-one relationship, not a one-to-many relationship.

Why do relational database is used primary keys in foreign keys?

A relational database is designed to enforce the uniqueness of primary keys by allowing only one row with a given primary key value in a table. A foreign key is a column or a set of columns in a table whose values correspond to the values of the primary key in another table.

Expert · Answer

Primary keys always need to be unique, foreign keys need to allow non-unique values if the table is a one-to-many relationship. It is perfectly fine to use a foreign key as the primary key if the table is connected by a one-to-one relationship, not a one-to-many relationship.

Expert · Answer

A relational database is designed to enforce the uniqueness of primary keys by allowing only one row with a given primary key value in a table. A foreign key is a column or a set of columns in a table whose values correspond to the values of the primary key in another table.

Why do we use primary keys for foreign keys?

Do you need a primary key if you have a foreign key?

Why do relational database is used primary keys in foreign keys?

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