Foreign key on_delete: :cascade - when parent is deleted delete a child

Edit

equivalent Web Development

May 28, 2025

Public

Rails

PostgreSQL

When you add a foreign key with on_delete: :cascade, you’re telling the database:

“If the parent record is deleted, automatically delete all related child records too.”

class CrePartyRepresentingClients < ActiveRecord::Migration[7.2]
  def change
    create_table :party_representing_clients do |t|
      t.references :party, null: false,  foreign_key: {on_delete: :cascade}
      t.references :client, null: false,  foreign_key: {to_table: :parties, on_delete: :cascade}
      t.timestamps
    end
  end
end

add_foreign_key :party_representing_clients, :parties, column: :party_id, on_delete: :cascade
add_foreign_key :party_representing_clients, :parties, column: :client_id, on_delete: :cascade