Programming

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I accidentally removed the WHERE clause from my SQL query in a personal tool. Every row is now the same. I overwrote 206,000+ rows. I have no backup, I am stupid. (lemmy.world)

submitted 1 year ago* (last edited 1 year ago) by [email protected] to c/programming

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"UPDATE table_name SET w = $1, x = $2, z = $4 WHERE y = $3 RETURNING *",

does not do the same as

"UPDATE table_name SET w = $1, x = $2, y = $3, z = $4 RETURNING *",

It's 2 am and my mind blanked out the WHERE, and just wanted the numbers neatly in order of 1234.

idiot.

FML.

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[–] MarekKnapek 4 points 1 year ago

Sh1t already happened, but on the bright side, you learn for the next time. Some tips:

Make clone of production environment into testing environment. Do stuff there, and after it is tested / verified, do the same in production. Emphasis on "do exactly the same".
Make regular automatic backup. From time to time, do a backup restore to another computer (VM) and verify that it is restored successfully and is actually usable.
Poor man's backup is automatic daily (hourly?) snapshots on BTRFS / ZFS / EXT4 filesystems or VolumeShadowCopy on NTFS filesystem.
Before any UPDATE do a SELECT and verify the data you are modifying are the data you actually want to modify.
Use a transactions in form of BEGIN TRANSACTION; UPDATE stuff; ROLLBACK; and observe the DB behavior, or see how many rows are affected.
Somebody has even moar tips, I'm sure. Please write them below.