Best way to delete all variables when uninstalling module

Question

I'm writing a module that writes several variables (three, four variables for every content type, and other).

Which method should I use to delete them on hook_uninstall?

Is it safe to perform a query, searching "mymodule_*" variables?

Or should I loop for content types and search variabels, so call many times variable_del?

Instead of creating variables named per content type, you could use a structured variable(s) which has a known name and keys for each content type? — Chris Burgess, Commented Dec 10, 2014 at 17:55

Clive · Accepted Answer · 2014-12-03 09:55:36Z

10

Variables are cached, so deleting manually is fine so long as you invalidate that cache, e.g.

db_delete('variable')
  ->condition('name', 'mymodule_%', 'LIKE')
  ->execute();

cache_clear_all('variables', 'cache_bootstrap');

answered Dec 3, 2014 at 9:55

Clive♦

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This query is OK provided that no-one has created a module which sits within your module namespace - eg if Views did this, it would vape variables belonging to modules like Views Block or Views MysiteCustom. For this example that probably wouldn't be a major issue, but you get the idea :)
– Chris Burgess
Commented Dec 9, 2014 at 23:13

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Chris Burgess · Accepted Answer · 2014-12-09 23:15:02Z

1

You also might look into the Variable module which allows your module to use a registry, configure default values and so forth.

answered Dec 9, 2014 at 23:15

Chris Burgess

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