Updating the database schema

Adding a revision

• Add a new revision to res/schema.xml, which is parsed by src/database/schemamanager
  • Increment the version attribute by one from the previous one
  • Use the min_compatible version from the previous revision unless you delete or rename a table or column
• Summarize your changes in the description subtag for future reference
• Add SQLite statements in the sql subtag

Using the revision

• Update MixxxDB::kRequiredVersion in src/database/mixxxdb.cpp to the new version
• Add tests to make sure your additions function as expected :)

Note that, once a revision is upgraded to, changes to it won't be recognized - so if you want to fix something afterwards you either have to change the version a few times or always work with a fresh database. Thus, once a revision is in master, it may not be modified bar extraordinary circumstances.