How to Reset a Database in PostgreSQL

What does “resetting” a PostgreSQL database really mean?

In PostgreSQL, there is no single RESET DATABASE statement. "Reset" normally implies either truncating all tables inside the current database or dropping and recreating the database itself.

How do you wipe all rows but keep the tables and sequences?

Run a single TRUNCATE … RESTART IDENTITY CASCADE.It removes data, clears foreign-key dependencies, and restarts serial sequences back to 1.

BEGIN;
TRUNCATE TABLE
"OrderItems",
"Orders",
"Products",
"Customers"
RESTART IDENTITY CASCADE;
COMMIT;

How do you drop and recreate the entire database?

Use DROP DATABASE followed by CREATE DATABASE.You need superuser or the database owner privileges and must connect to a different database (usually postgres) before dropping.

-- From psql connected to the maintenance DB
dropdb myshop;
createdb myshop -T template0;


Can you reset by recreating the public schema only?

If you want a clean schema without disconnecting users, drop and recreate the public schema.

BEGIN;
DROP SCHEMA public CASCADE;
CREATE SCHEMA public;
GRANT ALL ON SCHEMA public TO public;
COMMIT;

Which method should I choose?

Choose TRUNCATE when you only need to empty data during tests.Choose DROP DATABASE when you must change encoding, collation, or fully wipe everything quickly.

How do you script a test-environment reset?

Combine TRUNCATE with sequence resets inside a transaction. This keeps constraints valid and avoids temporary inconsistencies.

BEGIN;
TRUNCATE TABLE "OrderItems", "Orders", "Products", "Customers" RESTART IDENTITY CASCADE;
COMMIT;

Best practices for resetting safely?

1) Always back up first with pg_dump. 2) Disconnect application sessions before DROP DATABASE.3) Use explicit table lists; wildcards don’t work in TRUNCATE.

What happens to indexes, constraints, and grants?

TRUNCATE keeps structure intact, so indexes, constraints, and permissions stay.DROP DATABASE removes everything, including ownership grants.

How do you reset only a specific tenant’s data?

Instead of truncating, delete rows with WHERE customer_id = … and then reset relevant sequences via ALTER SEQUENCE.

Example: reset one customer

DELETE FROM "Orders" WHERE customer_id = 42;
SELECT setval(pg_get_serial_sequence('Orders','id'), 1, false);


Key takeaways

Use TRUNCATE … RESTART IDENTITY for quick data wipes. Use DROP DATABASE or DROP SCHEMA for full resets.Always confirm you are connected to the right database before running destructive commands.

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