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20 lip 2009 · JOIN information_schema.constraint_column_usage AS ccu. ON ccu.constraint_name = tc.constraint_name. WHERE constraint_type = 'FOREIGN KEY' AND ccu.table_name='YourTableNameHere'; This will list all the tables that use your specified table as a foreign key.
In PostgreSQL, a foreign key is a column or a group of columns in a table that uniquely identifies a row in another table. A foreign key establishes a link between the data in two tables by referencing the primary key or a unique constraint of the referenced table.
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.
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.
5 sty 2024 · In PostgreSQL, foreign keys help to maintain consistent and reliable relationships between datasets. Adding a Foreign Key to an Existing Table. Here’s how you add a foreign key constraint to an existing table: ALTER TABLE child_table ADD CONSTRAINT fk_name FOREIGN KEY (column1) REFERENCES parent_table (column2);
PostgreSQL Foreign Key Constraint. In PostgreSQL, the foreign key is a column(s) in a table that points to a primary key or unique key column in the same or another table. Foreign key establishes referential integrity between the parent and child tables.
26 wrz 2024 · Foreign Keys #. Recall the weather and cities tables from Chapter 2. Consider the following problem: You want to make sure that no one can insert rows in the weather table that do not have a matching entry in the cities table. This is called maintaining the referential integrity of your data.
