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.

注

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.