Manual:SQL patch file/en

You might write an SQL file either for a schema change in the core (see Development_policy#Database_patches, ) or for an extension (see ). See also the general database coding conventions.

Example
An SQL file to create a table might look something like this:

Variable replacement
The first two need to be used in patch files, as in the example above.


 * $1 will be replaced with $2.
 * $1 is used to identify indexes so their name can be changed via the index alias system. (This was only ever used for a small number of core tables and has been removed in MediaWiki 1.35, so in practice this does not make any difference.)
 * $1 will be replaced with the value of $2.
 * is only used for database backends.

There are other variable replacements but they are not used in practice. See the documentation of $1 for the full list.