x/sqlalchemy-migrate
Code Issues Proposed changes

Fix dropping of indexed columns in sqlite/sa08

Browse Source 
Version 0.8 of SQLAlchemy added support of indexes
on expressions in addition to plain table columns,
which changed the way indexes are created.

This broke support of dropping columns of composite
indexes for SQLite: due to limitations of ALTER in
SQLite every time a column is dropped, we recreate
the whole table without the given column; if a
column is a part of a composite index, we change the
index definition to omit that column and then indexes
are recreated too.

SQLAlchemy versions starting from 0.8 no more pay
attention to 'columns' attribute of Index instances
when generating DDL for indexes, so when one of columns
of a composite index is dropped, we try to create a
new index on the column that doesn't exist anymore,
which of course fails.

Closes-Bug: #1241038

Change-Id: I777b8ce36e36f49bfb0889908811a063cf1a527b
This commit is contained in:
Roman Podolyaka 2013-10-18 14:23:11 +03:00
parent a91766a1ac
commit 2485118c24
3 changed files with 39 additions and 3 deletions
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1
migrate/changeset/__init__.py
View File

@ -14,6 +14,7 @@ warnings.simplefilter('always', DeprecationWarning)
_sa_version = tuple(int(re.match("\d+", x).group(0)) for x in _sa_version.split("."))
SQLA_07 = _sa_version >= (0, 7)
SQLA_08 = _sa_version >= (0, 8)
del re
del _sa_version

6
migrate/changeset/schema.py
View File

@ -11,7 +11,7 @@ from sqlalchemy.schema import ForeignKeyConstraint
from sqlalchemy.schema import UniqueConstraint
from migrate.exceptions import *
from migrate.changeset import SQLA_07
from migrate.changeset import SQLA_07, SQLA_08
from migrate.changeset.databases.visitor import (get_engine_visitor,
run_single_visitor)
@ -573,7 +573,9 @@ populated with defaults
if col.name!=self.name:
columns.append(col)
if columns:
index.columns=columns
index.columns = columns
if SQLA_08:
index.expressions = columns
else:
to_drop.add(index)
table.indexes = table.indexes - to_drop

35
migrate/tests/changeset/test_changeset.py
View File

@ -18,6 +18,7 @@ class TestAddDropColumn(fixture.DB):
"""
level = fixture.DB.CONNECT
table_name = 'tmp_adddropcol'
table_name_idx = 'tmp_adddropcol_idx'
table_int = 0
def _setup(self, url):
@ -26,14 +27,27 @@ class TestAddDropColumn(fixture.DB):
self.table = Table(self.table_name, self.meta,
Column('id', Integer, unique=True),
)
self.table_idx = Table(
self.table_name_idx,
self.meta,
Column('id', Integer, primary_key=True),
Column('a', Integer),
Column('b', Integer),
Index('test_idx', 'a', 'b')
)
self.meta.bind = self.engine
if self.engine.has_table(self.table.name):
self.table.drop()
if self.engine.has_table(self.table_idx.name):
self.table_idx.drop()
self.table.create()
self.table_idx.create()
def _teardown(self):
if self.engine.has_table(self.table.name):
self.table.drop()
if self.engine.has_table(self.table_idx.name):
self.table_idx.drop()
self.meta.clear()
super(TestAddDropColumn,self)._teardown()
@ -257,7 +271,26 @@ class TestAddDropColumn(fixture.DB):
col.drop(self.table)
# TODO: remove already attached columns with indexes, uniques, pks, fks ..
# TODO: remove already attached columns with uniques, pks, fks ..
@fixture.usedb(not_supported='postgresql')
def test_drop_column_of_composite_index(self):
# NOTE(rpodolyaka): postgresql automatically drops a composite index
# if one of its columns is dropped
self.table_idx.c.b.drop()
reflected = Table(self.table_idx.name, MetaData(), autoload=True,
autoload_with=self.engine)
index = next(iter(reflected.indexes))
self.assertEquals(['a'], [c.name for c in index.columns])
@fixture.usedb()
def test_drop_all_columns_of_composite_index(self):
self.table_idx.c.a.drop()
self.table_idx.c.b.drop()
reflected = Table(self.table_idx.name, MetaData(), autoload=True,
autoload_with=self.engine)
self.assertEquals(0, len(reflected.indexes))
def _check_index(self,expected):
if 'mysql' in self.engine.name or 'postgres' in self.engine.name: