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20 lip 2009 · You can do this via the information_schema tables. For example: SELECT tc.table_schema, tc.constraint_name, tc.table_name, kcu.column_name, ccu.table_schema AS foreign_table_schema, ccu.table_name AS foreign_table_name, ccu.column_name AS foreign_column_name FROM information_schema.table_constraints AS tc JOIN information_schema.key_column ...
The FOREIGN KEY constraint is used to prevent actions that would destroy links between tables. A FOREIGN KEY is a field (or collection of fields) in one table, that refers to the PRIMARY KEY in another table.
ALTER TABLE child_table_name ADD FOREIGN KEY (child_table_column) REFERENCES parent_table_name(parent_table_column); child_table_name is that table in which we want to add constraint. child_table_column is that table column in which we want to add foreign key.
5 sty 2024 · In PostgreSQL, modifying foreign key constraints in existing tables is a common administrative task, essential for maintaining data integrity. This tutorial walks through the steps to add and update foreign keys with practical examples.
The FOREIGN KEY constraint is a key used to link two tables together. A FOREIGN KEY is a field (or collection of fields) in one table that refers to the PRIMARY KEY in another table.
In this tutorial, you will learn about PostgreSQL foreign key and how to add foreign keys to tables using foreign key constraints.
19 mar 2013 · Returns all primary and foreign keys for all tables in the given schema, ordered by tablename, PKs first. The manual about pg_constraint . The manual about object identifier types ( regclass , regnamespace , ...).
