Cascade delete postgres how to#

There will be one too many relationships between teams and developers’ tables. Step 2: Now, we will create a table for developers which will act as the referencing or child table. Step 1: Firstly, let us create a table for teams which will be our main referenced parent table. While maintaining both records in the database, we will first create tables for each one of them. Each developer belongs to one or the other team, and one team is made of many developers. The example will contain two tables, namely teams, and developers. Here, we will learn how we can use delete cascade in PostgreSQL with the help of an example.

When we use the DELETE CASCADE feature, deleting the referenced entry (parent record) results in the automatic deletion of all its referencing records (child records). We can set up foreign keys to prevent manipulation of referenced records when there are corresponding referencing records in other tables. When we come across a table containing one or more records, where a field or group of fields uniquely represents records from another table, we assign the label of “referencing table” or “child table” to the first table and the label of “referenced table” or “parent table” to the table whose records are being referenced. Hence, it is first necessary to understand what is the foreign key.

Cascade delete postgres how to#

How to use Postgres Delete Cascadeĭelete cascade is only used when the tables involve foreign key constraints. When we specify the foreign key constraint in the referencing table using the “ON DELETE CASCADE” keywords, it indicates that the operation performed on the referenced table should cascade to the referencing records.