A template for adding indexes via a South migration

0002_indexes.py

# -*- coding: utf-8 -*-

import copy

from south.db import db
from south.v2 import SchemaMigration

###
# CHANGE THESE VALUES TO FIT YOUR PROJECT
INDEXES = (
    ('table_name', 'column_name', 'index_name'),
    ('other_table_name', ('column_one', 'column_two'), 'other_index_name'),
)
PREVIOUS_MIGRATION = 'api.migrations.0001_initial'
#
###


previous_migration = __import__(PREVIOUS_MIGRATION, globals(), locals(), ['Migration'], -1)


class Migration(SchemaMigration):
    """This migration is for adding some indexes to some columns

    References:
    http://www.postgresql.org/docs/9.1/static/sql-createindex.html
    http://www.postgresql.org/docs/9.2/static/sql-dropindex.html
    """
    

    def forwards(self, orm):
        for index in INDEXES:
            table, columns, index_name = index
            if not isinstance(columns, basestring):
              columns = '(' + ', '.join(columns) + ')'
            query = "CREATE INDEX %s ON %s (%s) ;" % (index_name,
                                                     table,
                                                     column)
            db.execute(query)

    def backwards(self, orm):
        for index in INDEXES:
            table, columns, index_name = index
            query = "DROP INDEX %s ;" % index_name
            db.execute(query)

    models = copy.deepcopy(previous_migration.Migration.models)
    complete_apps = copy.deepcopy(previous_migration.Migration.complete_apps)