Klausa RETURNING ngidini statement INSERT, UPDATE, lan DELETE bali data babagan baris sing diarani — paling umum ID sing dibuat otomatis sawise insert, nanging uga kolom utawa nilai sing diitung. Éta nyimpen query sing kapisah lan minangka fitur PostgreSQL sing praktis.
-- get the auto-generated id back from the insert (no separate SELECT needed)
INSERT INTO users (name, email) VALUES ('Ann', '[email protected]')
RETURNING id; -- returns the new id
-- return multiple columns or all of them
INSERT INTO users (name) VALUES ('Bob')
RETURNING id, name, created_at; -- including DB-generated values
INSERT INTO users (name) VALUES ('Carol') RETURNING *; -- the whole row
Penggunaan paling umum: sawise ngisor, sampeyan biasane butuh primary key sing dibuat (kanggo digunakake ing insert sing ana gandhengane utawa dikembalikan menyang klien). RETURNING id menehi maneh langsung — ora perlu query sing kapisah.
-- see what was updated
UPDATE products SET price = price * 1.1 WHERE category = 'books'
RETURNING id, name, price; -- the NEW values after the update
-- capture deleted rows (e.g. for archiving/logging)
DELETE FROM sessions WHERE expired = true
RETURNING id, user_id; -- which rows were deleted
RETURNING makarya ing UPDATE (ndelok nilai anyar) lan DELETE (nangkep apa sing dibusak — migunani kanggo ngarsipi utawa ngoneksekusi).
Without RETURNING:
INSERT ...; then a separate SELECT to get the id → TWO round-trips, and a potential
race (the SELECT might not reliably get YOUR row).
With RETURNING:
one statement returns the affected data atomically → fewer round-trips, no race.
-- use a CTE with RETURNING to insert and use the id in the same statement
WITH new_user AS (
INSERT INTO users (name) VALUES ('Ann') RETURNING id
)
INSERT INTO profiles (user_id, bio)
SELECT id, 'Hello' FROM new_user; -- use the returned id directly
Klausa RETURNING minangka fitur PostgreSQL sing praktis lan asring digunakake sing berharga kanggo efisiensi lan kebeneran nalika ngowahi data.
Penggunaan paling umum lan penting yaiku nggayuh ID sing dibuat otomatis bali saka INSERT — kabutuhan sing meh universal (sampeyan meh tansah butuh primary key anyar sawise ngisor, kanggo digunakake ing operasi sing ana gandhengane utawa dikembalikan menyang aplikasi), lan RETURNING id nyedhiyakake langsung ing siji statement.
Tanpa RETURNING, sampeyan butuh SELECT sing kapisah kanggo nggayuh ID sing dibuat, tegese round-trip tambahan lan kondisi balapan potensial (SELECT sing kapisah bisa uga ora bisa nyedhiakake baris spesifik sampeyan kanthi handal ing skenario concurrent), mula RETURNING luwih efisien lan luwih bener.
\n Saliyane inserts, RETURNING makarya karo UPDATE (ndelok nilai anyar sawise update) lan DELETE (nangkep apa sing dibusak — migunani kanggo ngarsipi, ngloga, utawa ngoneksekusi brosing).
Gabung karo CTEs, éta ngidini pola kuat kaya ngisor menyang tabel sing ana gandhengane nggunakake ID sing bali ing siji statement.
Dadéyan nggayuh nilai sing dibuat (utamané IDs) sawise modifikasi data minangka kabutuhan konstan, lan amarga RETURNING nyedhiyakake éta kanthi efisien lan atomis (nyegah query tambahan lan kondisi balapan), ngerti klausa RETURNING minangka pengetahuan PostgreSQL sing berharga, asring diterapake sing ngawé kode modifikasi data luwih resik, luwih efisien, lan luwih bener — kenyamanan praktis sing digunakake kanthi rutin ing aplikasi nyata sing makarya karo Postgres, utamané kanggo kabutuhan ubikuitous kanggo ngambil IDs sing dibuat sawise inserts.