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MySQL – I Am a Dummy


Today I learned about an interesting command-line option for MySQL:
$ mysql --i-am-a-dummy
This is an alias for --safe-updates, which imposes three restrictions:

  1. Any UPDATE or DELETE that does not have a WHERE or LIMIT is rejected.
  2. Any SELECT without a LIMIT will be automatically limited to 1,000 rows in the result.
  3. Any join that would result in examining more than a million row combinations is rejected.

I thought it was funny at first, but the first restriction alone makes this useful for doing work on the command-line on live servers.  You ever intend to do something like DELETE FROM users WHERE id = … and you forget that tiny little where-clause?  Because I have, and all you want to do is hide under your desk, under the assumption that if no one can see you then you must be invisible.