import sqlalchemy

from sqlalchemy.databases import postgres

class AutoLoader(object):

pass

class PGIndexLoader(AutoLoader):

""" SA does not load indexes for us """

sql4indexes = "SELECT indexname, tablename, indexdef FROM pg_indexes"

def __init__(self, db):

ix = {}

for name, tbl_name, sqltext in db.execute(self.sql4indexes):

ix.setdefault(tbl_name, []).append( (name, sqltext) )

self._indexes = ix

def indexes(self, table):

return [self._index_from_def(name, sqltext, table)

for name, sqltext in self._indexes.get(table.name, ())]

def _index_from_def(self, name, sqltext, table):

# CREATE UNIQUE INDEX name ON "tablename" USING btree (columnslist)

unique = ' UNIQUE ' in sqltext

cols = sqltext.split(' (')[1].split(')')[0].split(',')

cols = [table.columns[cname.strip().replace('"', '')]

for cname in cols]

name = name.encode('utf-8')

return sqlalchemy.Index(name, unique=unique, *cols)

postgres.PGDialect.indexloader = PGIndexLoader