sqlite.py
148 lines
| 5.0 KiB
| text/x-python
|
PythonLexer
r833 | """ | |||
`SQLite`_ database specific implementations of changeset classes. | ||||
.. _`SQLite`: http://www.sqlite.org/ | ||||
""" | ||||
from UserDict import DictMixin | ||||
from copy import copy | ||||
from sqlalchemy.databases import sqlite as sa_base | ||||
from migrate import exceptions | ||||
from migrate.changeset import ansisql, SQLA_06 | ||||
if not SQLA_06: | ||||
SQLiteSchemaGenerator = sa_base.SQLiteSchemaGenerator | ||||
else: | ||||
SQLiteSchemaGenerator = sa_base.SQLiteDDLCompiler | ||||
class SQLiteCommon(object): | ||||
def _not_supported(self, op): | ||||
raise exceptions.NotSupportedError("SQLite does not support " | ||||
"%s; see http://www.sqlite.org/lang_altertable.html" % op) | ||||
class SQLiteHelper(SQLiteCommon): | ||||
def recreate_table(self,table,column=None,delta=None): | ||||
table_name = self.preparer.format_table(table) | ||||
# we remove all indexes so as not to have | ||||
# problems during copy and re-create | ||||
for index in table.indexes: | ||||
index.drop() | ||||
self.append('ALTER TABLE %s RENAME TO migration_tmp' % table_name) | ||||
self.execute() | ||||
insertion_string = self._modify_table(table, column, delta) | ||||
table.create() | ||||
self.append(insertion_string % {'table_name': table_name}) | ||||
self.execute() | ||||
self.append('DROP TABLE migration_tmp') | ||||
self.execute() | ||||
def visit_column(self, delta): | ||||
if isinstance(delta, DictMixin): | ||||
column = delta.result_column | ||||
table = self._to_table(delta.table) | ||||
else: | ||||
column = delta | ||||
table = self._to_table(column.table) | ||||
self.recreate_table(table,column,delta) | ||||
class SQLiteColumnGenerator(SQLiteSchemaGenerator, | ||||
ansisql.ANSIColumnGenerator, | ||||
# at the end so we get the normal | ||||
# visit_column by default | ||||
SQLiteHelper, | ||||
SQLiteCommon | ||||
): | ||||
"""SQLite ColumnGenerator""" | ||||
def _modify_table(self, table, column, delta): | ||||
columns = ' ,'.join(map( | ||||
self.preparer.format_column, | ||||
[c for c in table.columns if c.name!=column.name])) | ||||
return ('INSERT INTO %%(table_name)s (%(cols)s) ' | ||||
'SELECT %(cols)s from migration_tmp')%{'cols':columns} | ||||
def visit_column(self,column): | ||||
if column.foreign_keys: | ||||
SQLiteHelper.visit_column(self,column) | ||||
else: | ||||
super(SQLiteColumnGenerator,self).visit_column(column) | ||||
class SQLiteColumnDropper(SQLiteHelper, ansisql.ANSIColumnDropper): | ||||
"""SQLite ColumnDropper""" | ||||
def _modify_table(self, table, column, delta): | ||||
columns = ' ,'.join(map(self.preparer.format_column, table.columns)) | ||||
return 'INSERT INTO %(table_name)s SELECT ' + columns + \ | ||||
' from migration_tmp' | ||||
class SQLiteSchemaChanger(SQLiteHelper, ansisql.ANSISchemaChanger): | ||||
"""SQLite SchemaChanger""" | ||||
def _modify_table(self, table, column, delta): | ||||
return 'INSERT INTO %(table_name)s SELECT * from migration_tmp' | ||||
def visit_index(self, index): | ||||
"""Does not support ALTER INDEX""" | ||||
self._not_supported('ALTER INDEX') | ||||
class SQLiteConstraintGenerator(ansisql.ANSIConstraintGenerator, SQLiteHelper, SQLiteCommon): | ||||
def visit_migrate_primary_key_constraint(self, constraint): | ||||
tmpl = "CREATE UNIQUE INDEX %s ON %s ( %s )" | ||||
cols = ', '.join(map(self.preparer.format_column, constraint.columns)) | ||||
tname = self.preparer.format_table(constraint.table) | ||||
name = self.get_constraint_name(constraint) | ||||
msg = tmpl % (name, tname, cols) | ||||
self.append(msg) | ||||
self.execute() | ||||
def _modify_table(self, table, column, delta): | ||||
return 'INSERT INTO %(table_name)s SELECT * from migration_tmp' | ||||
def visit_migrate_foreign_key_constraint(self, *p, **k): | ||||
self.recreate_table(p[0].table) | ||||
def visit_migrate_unique_constraint(self, *p, **k): | ||||
self.recreate_table(p[0].table) | ||||
class SQLiteConstraintDropper(ansisql.ANSIColumnDropper, | ||||
SQLiteCommon, | ||||
ansisql.ANSIConstraintCommon): | ||||
def visit_migrate_primary_key_constraint(self, constraint): | ||||
tmpl = "DROP INDEX %s " | ||||
name = self.get_constraint_name(constraint) | ||||
msg = tmpl % (name) | ||||
self.append(msg) | ||||
self.execute() | ||||
def visit_migrate_foreign_key_constraint(self, *p, **k): | ||||
self._not_supported('ALTER TABLE DROP CONSTRAINT') | ||||
def visit_migrate_check_constraint(self, *p, **k): | ||||
self._not_supported('ALTER TABLE DROP CONSTRAINT') | ||||
def visit_migrate_unique_constraint(self, *p, **k): | ||||
self._not_supported('ALTER TABLE DROP CONSTRAINT') | ||||
# TODO: technically primary key is a NOT NULL + UNIQUE constraint, should add NOT NULL to index | ||||
class SQLiteDialect(ansisql.ANSIDialect): | ||||
columngenerator = SQLiteColumnGenerator | ||||
columndropper = SQLiteColumnDropper | ||||
schemachanger = SQLiteSchemaChanger | ||||
constraintgenerator = SQLiteConstraintGenerator | ||||
constraintdropper = SQLiteConstraintDropper | ||||