https://www.postgresqltutorial.com › postgresql-tutorial › postgresql-identity-column

This tutorial shows you how to use the GENERATED AS IDENTITY constraint to create the PostgreSQL identity column for a table.

https://docs.postgresql.fr › 17 › ddl-identity-columns.html

Une colonne d'identité est une colonne spéciale qui est générée automatiquement à partir d'une séquence implicite. Elle peut être utilisée pour générer des valeurs de clé. Pour créer une colonne d'identité, utilisez la clause GENERATED ... AS IDENTITY de la commande CREATE TABLE, par exemple :

https://stackoverflow.com › questions › 2944499

Suppose you have a table table_name, to which you want to add an auto-incrementing, primary-key id (surrogate) column. The recommended way is using the form GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( sequence_options ) ]. e.g. ALTER TABLE table_name ADD COLUMN id INTEGER PRIMARY KEY GENERATED ALWAYS AS IDENTITY; or

https://www.postgresql.org › docs › current › ddl-identity-columns.html

During INSERT or UPDATE, a column is treated as an identity column if that column is an identity column in the table named in the statement, and the corresponding identity properties are applied. Partitions inherit identity columns from the partitioned table. They cannot have their own identity columns. The properties of a given identity column ...

https://database.guide › create-an-identity-column-in-postgresql

The following syntax applies to creating an identity column in PostgreSQL: GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( sequence_options ) ] This is applied to the column, within the definition for the table.

https://www.postgresql.org › docs › current › sql-createtable.htm

This clause creates the column as an identity column. It will have an implicit sequence attached to it and in newly-inserted rows the column will automatically have values from the sequence assigned to it. Such a column is implicitly NOT NULL.

https://www.rockdata.net › tutorial › ddl-identity-column

Summary: In this tutorial, you will learn how to use the GENERATED AS IDENTITY constraint to create the PostgreSQL identity column for a table. Table of Contents. Introduction to PostgreSQL identity column; PostgreSQL identity column examples. A) GENERATED ALWAYS example; B) GENERATED BY DEFAULT AS IDENTITY example; C) Sequence ...

https://www.enterprisedb.com › blog › postgresql-10-identity-columns-explained

For PostgreSQL 10, I have worked on a feature called “identity columns”. Depesz already wrote a blog post about it and showed that it works pretty much like serial columns: CREATE TABLE test_old ( id serial PRIMARY KEY, payload text ); INSERT INTO test_old (payload) VALUES ('a'), ('b'), ('c') RETURNING *; and

https://www.postgresql.org › docs › current › sql-altertable.htm

These forms change whether a column is an identity column or change the generation attribute of an existing identity column. See CREATE TABLE for details. Like SET DEFAULT , these forms only affect the behavior of subsequent INSERT and UPDATE commands; they do not cause rows already in the table to change.