forked from openlp/openlp
72 lines
2.9 KiB
Python
72 lines
2.9 KiB
Python
# -*- coding: utf-8 -*-
|
|
|
|
##########################################################################
|
|
# OpenLP - Open Source Lyrics Projection #
|
|
# ---------------------------------------------------------------------- #
|
|
# Copyright (c) 2008-2022 OpenLP Developers #
|
|
# ---------------------------------------------------------------------- #
|
|
# This program is free software: you can redistribute it and/or modify #
|
|
# it under the terms of the GNU General Public License as published by #
|
|
# the Free Software Foundation, either version 3 of the License, or #
|
|
# (at your option) any later version. #
|
|
# #
|
|
# This program is distributed in the hope that it will be useful, #
|
|
# but WITHOUT ANY WARRANTY; without even the implied warranty of #
|
|
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the #
|
|
# GNU General Public License for more details. #
|
|
# #
|
|
# You should have received a copy of the GNU General Public License #
|
|
# along with this program. If not, see <https://www.gnu.org/licenses/>. #
|
|
##########################################################################
|
|
"""
|
|
The :mod:`db` module provides helper functions for database related methods.
|
|
"""
|
|
import logging
|
|
from copy import deepcopy
|
|
|
|
import sqlalchemy
|
|
|
|
|
|
log = logging.getLogger(__name__)
|
|
|
|
|
|
def drop_column(op, tablename, columnname):
|
|
drop_columns(op, tablename, [columnname])
|
|
|
|
|
|
def drop_columns(op, tablename, columns):
|
|
"""
|
|
Column dropping functionality for SQLite, as there is no DROP COLUMN support in SQLite
|
|
|
|
From https://github.com/klugjohannes/alembic-sqlite
|
|
"""
|
|
|
|
# get the db engine and reflect database tables
|
|
engine = op.get_bind()
|
|
meta = sqlalchemy.MetaData(bind=engine)
|
|
meta.reflect()
|
|
|
|
# create a select statement from the old table
|
|
old_table = meta.tables[tablename]
|
|
select = sqlalchemy.sql.select([c for c in old_table.c if c.name not in columns])
|
|
|
|
# get remaining columns without table attribute attached
|
|
remaining_columns = [deepcopy(c) for c in old_table.columns if c.name not in columns]
|
|
for column in remaining_columns:
|
|
column.table = None
|
|
|
|
# create a temporary new table
|
|
new_tablename = '{0}_new'.format(tablename)
|
|
op.create_table(new_tablename, *remaining_columns)
|
|
meta.reflect()
|
|
new_table = meta.tables[new_tablename]
|
|
|
|
# copy data from old table
|
|
insert = sqlalchemy.sql.insert(new_table).from_select([c.name for c in remaining_columns], select)
|
|
engine.execute(insert)
|
|
|
|
# drop the old table and rename the new table to take the old tables
|
|
# position
|
|
op.drop_table(tablename)
|
|
op.rename_table(new_tablename, tablename)
|