Database migration

Casdoor uses xorm for database access. Xorm handles many schema changes automatically, but renaming columns and some data migrations must be done manually via the xorm migrate package.

nota

See the xorm documentation for schema operation details.

How it works

Xorm does not rename columns automatically. To rename a field (e.g. p_type → ptype), you add a migration that copies data and then drops the old column.

Example migration:

migrations := []*migrate.Migration{
        {
            ID: "CasbinRule--fill ptype field with p",
            Migrate: func(tx *xorm.Engine) error {
                _, err := tx.Cols("ptype").Update(&xormadapter.CasbinRule{
                    Ptype: "p",
                })
                return err
            },
            Rollback: func(tx *xorm.Engine) error {
                return tx.DropTables(&xormadapter.CasbinRule{})
            },
        },
    }
    m.Migrate()

Here the goal is to rename p_type to ptype: copy values into ptype, then drop p_type (handled elsewhere). The migration ID is stored in the database; on subsequent starts, migrations with an existing ID are skipped.