Fixed #2635 -- Added improved MySQL backend support from Andy Dustman. Also

added database.txt documentation; currently only describing Django-related
features of MySQL versions.

As of this commit, there are four known test failures due to (a) no transaction
support with MyISAM storage engine and (b) MySQLdb automatically creating
decimal types for Django's "float" field.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@4724 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Malcolm Tredinnick 2007-03-14 12:08:19 +00:00
parent 7ccf9978ad
commit f9c4ce5123
5 changed files with 210 additions and 45 deletions

View File

@ -10,6 +10,9 @@ try:
except ImportError, e: except ImportError, e:
from django.core.exceptions import ImproperlyConfigured from django.core.exceptions import ImproperlyConfigured
raise ImproperlyConfigured, "Error loading MySQLdb module: %s" % e raise ImproperlyConfigured, "Error loading MySQLdb module: %s" % e
if Database.version_info < (1,2,1,'final',2):
raise ImportError, "MySQLdb-1.2.1p2 or newer is required; you have %s" % MySQLdb.__version__
from MySQLdb.converters import conversions from MySQLdb.converters import conversions
from MySQLdb.constants import FIELD_TYPE from MySQLdb.constants import FIELD_TYPE
import types import types
@ -17,11 +20,14 @@ import re
DatabaseError = Database.DatabaseError DatabaseError = Database.DatabaseError
# MySQLdb-1.2.1 supports the Python boolean type, and only uses datetime
# module for time-related columns; older versions could have used mx.DateTime
# or strings if there were no datetime module. However, MySQLdb still returns
# TIME columns as timedelta -- they are more like timedelta in terms of actual
# behavior as they are signed and include days -- and Django expects time, so
# we still need to override that.
django_conversions = conversions.copy() django_conversions = conversions.copy()
django_conversions.update({ django_conversions.update({
types.BooleanType: util.rev_typecast_boolean,
FIELD_TYPE.DATETIME: util.typecast_timestamp,
FIELD_TYPE.DATE: util.typecast_date,
FIELD_TYPE.TIME: util.typecast_time, FIELD_TYPE.TIME: util.typecast_time,
}) })
@ -31,31 +37,12 @@ django_conversions.update({
# http://dev.mysql.com/doc/refman/5.0/en/news.html . # http://dev.mysql.com/doc/refman/5.0/en/news.html .
server_version_re = re.compile(r'(\d{1,2})\.(\d{1,2})\.(\d{1,2})') server_version_re = re.compile(r'(\d{1,2})\.(\d{1,2})\.(\d{1,2})')
# This is an extra debug layer over MySQL queries, to display warnings. # MySQLdb-1.2.1 and newer automatically makes use of SHOW WARNINGS on
# It's only used when DEBUG=True. # MySQL-4.1 and newer, so the MysqlDebugWrapper is unnecessary. Since the
class MysqlDebugWrapper: # point is to raise Warnings as exceptions, this can be done with the Python
def __init__(self, cursor): # warning module, and this is setup when the connection is created, and the
self.cursor = cursor # standard util.CursorDebugWrapper can be used. Also, using sql_mode
# TRADITIONAL will automatically cause most warnings to be treated as errors.
def execute(self, sql, params=()):
try:
return self.cursor.execute(sql, params)
except Database.Warning, w:
self.cursor.execute("SHOW WARNINGS")
raise Database.Warning, "%s: %s" % (w, self.cursor.fetchall())
def executemany(self, sql, param_list):
try:
return self.cursor.executemany(sql, param_list)
except Database.Warning, w:
self.cursor.execute("SHOW WARNINGS")
raise Database.Warning, "%s: %s" % (w, self.cursor.fetchall())
def __getattr__(self, attr):
if self.__dict__.has_key(attr):
return self.__dict__[attr]
else:
return getattr(self.cursor, attr)
try: try:
# Only exists in Python 2.4+ # Only exists in Python 2.4+
@ -83,28 +70,31 @@ class DatabaseWrapper(local):
def cursor(self): def cursor(self):
from django.conf import settings from django.conf import settings
from warnings import filterwarnings
if not self._valid_connection(): if not self._valid_connection():
kwargs = { kwargs = {
'user': settings.DATABASE_USER,
'db': settings.DATABASE_NAME,
'passwd': settings.DATABASE_PASSWORD,
'conv': django_conversions, 'conv': django_conversions,
} }
if settings.DATABASE_USER:
kwargs['user'] = settings.DATABASE_USER
if settings.DATABASE_NAME:
kwargs['db'] = settings.DATABASE_NAME
if settings.DATABASE_PASSWORD:
kwargs['passwd'] = settings.DATABASE_PASSWORD
if settings.DATABASE_HOST.startswith('/'): if settings.DATABASE_HOST.startswith('/'):
kwargs['unix_socket'] = settings.DATABASE_HOST kwargs['unix_socket'] = settings.DATABASE_HOST
else: elif settings.DATABASE_HOST:
kwargs['host'] = settings.DATABASE_HOST kwargs['host'] = settings.DATABASE_HOST
if settings.DATABASE_PORT: if settings.DATABASE_PORT:
kwargs['port'] = int(settings.DATABASE_PORT) kwargs['port'] = int(settings.DATABASE_PORT)
kwargs.update(self.options) kwargs.update(self.options)
self.connection = Database.connect(**kwargs) self.connection = Database.connect(**kwargs)
cursor = self.connection.cursor() cursor = self.connection.cursor()
if self.connection.get_server_info() >= '4.1':
cursor.execute("SET NAMES 'utf8'")
else: else:
cursor = self.connection.cursor() cursor = self.connection.cursor()
if settings.DEBUG: if settings.DEBUG:
return util.CursorDebugWrapper(MysqlDebugWrapper(cursor), self) filterwarnings("error", category=Database.Warning)
return util.CursorDebugWrapper(cursor, self)
return cursor return cursor
def _commit(self): def _commit(self):

View File

@ -3,12 +3,25 @@ import os
def runshell(): def runshell():
args = [''] args = ['']
args += ["--user=%s" % settings.DATABASE_USER] db = settings.DATABASE_OPTIONS.get('db', settings.DATABASE_NAME)
if settings.DATABASE_PASSWORD: user = settings.DATABASE_OPTIONS.get('user', settings.DATABASE_USER)
args += ["--password=%s" % settings.DATABASE_PASSWORD] passwd = settings.DATABASE_OPTIONS.get('passwd', settings.DATABASE_PASSWORD)
if settings.DATABASE_HOST: host = settings.DATABASE_OPTIONS.get('host', settings.DATABASE_HOST)
args += ["--host=%s" % settings.DATABASE_HOST] port = settings.DATABASE_OPTIONS.get('port', settings.DATABASE_PORT)
if settings.DATABASE_PORT: defaults_file = settings.DATABASE_OPTIONS.get('read_default_file')
args += ["--port=%s" % settings.DATABASE_PORT] # Seems to be no good way to set sql_mode with CLI
args += [settings.DATABASE_NAME]
if defaults_file:
args += ["--defaults-file=%s" % defaults_file]
if user:
args += ["--user=%s" % user]
if passwd:
args += ["--password=%s" % passwd]
if host:
args += ["--host=%s" % host]
if port:
args += ["--port=%s" % port]
if db:
args += [db]
os.execvp('mysql', args) os.execvp('mysql', args)

View File

@ -826,7 +826,7 @@ class TimeField(Field):
if value is not None: if value is not None:
# MySQL will throw a warning if microseconds are given, because it # MySQL will throw a warning if microseconds are given, because it
# doesn't support microseconds. # doesn't support microseconds.
if settings.DATABASE_ENGINE == 'mysql': if settings.DATABASE_ENGINE == 'mysql' and hasattr(value, 'microsecond'):
value = value.replace(microsecond=0) value = value.replace(microsecond=0)
value = str(value) value = str(value)
return Field.get_db_prep_save(self, value) return Field.get_db_prep_save(self, value)

162
docs/databases.txt Normal file
View File

@ -0,0 +1,162 @@
===============================
Notes About Supported Databases
===============================
Django attempts to support as many features as possible on all databases.
However, since not all database servers are identical, there is obviously
going to be some variations. This file describes some of the
features that might relevant to Django usage. It is not intended as a
replacement for server-specific documentation or reference manuals.
MySQL Notes
===========
Django expects the database to support transactions, referential integrity,
and Unicode support (UTF-8 encoding). Fortunately MySQL_ has all these
features as available as far back as 3.23. While it may be possible to use
3.23 or 4.0, you will probably have less trouble if you use 4.1 or 5.0.
MySQL-4.1
---------
MySQL-4.1_ has greatly improved support for character sets. It is possible to
set different default character sets on the database, table, and column.
Previous versions have only a server-wide character set setting. It's also the
first version where the character set can be changed on the fly. 4.1 also has
support for views, but these are not currently used by Django.
MySQL-5.0
---------
MySQL-5.0_ adds the ``information_schema`` database, which contains detailed
data on all database schema. This is used for Django's ``inspectdb`` feature,
when it is available. 5.0 also has support for stored procedures, but these
are not currently used by Django.
.. _MySQL: http://www.mysql.com/
.. _MySQL-4.1: http://dev.mysql.com/doc/refman/4.1/en/index.html
.. _MySQL-5.0: http://dev.mysql.com/doc/refman/5.0/en/index.html
Storage Engines
---------------
MySQL has several `storage engines`_ (previously called table types). You can
change the default storage engine in the server configuration.
The default one is MyISAM_. The main drawback of MyISAM is that it does not
currently have support for transactions or foreign keys. On the plus side, it
is currently the only engine that supports full-text indexing and searching.
The InnoDB_ engine is fully transactional and supports foreign key references.
The BDB_ engine, like InnoDB, is also fully transactional and supports foreign
key references. However, it's use seems to be somewhat deprecated.
`Other storage engines`_, including SolidDB_ and Falcon_, are on the horizon.
For now, InnoDB is probably your best choice.
.. _storage engines: http://dev.mysql.com/doc/refman/5.0/en/storage-engines.html
.. _MyISAM: http://dev.mysql.com/doc/refman/5.0/en/myisam-storage-engine.html
.. _BDB: http://dev.mysql.com/doc/refman/5.0/en/bdb-storage-engine.html
.. _InnoDB: http://dev.mysql.com/doc/refman/5.0/en/innodb.html
.. _Other storage engines: http://dev.mysql.com/doc/refman/5.1/en/storage-engines-other.html
.. _SolidDB: http://forge.mysql.com/projects/view.php?id=139
.. _Falcon: http://dev.mysql.com/doc/falcon/en/index.html
MySQLdb
-------
`MySQLdb`_ is the Python interface to MySQL. 1.2.1 is the first version which
has support for MySQL-4.1 and newer. If you are trying to use an older version
of MySQL, then 1.2.0 *may* work for you.
.. _MySQLdb: http://sourceforge.net/projects/mysql-python
Creating your database
~~~~~~~~~~~~~~~~~~~~~~
You can `create your database`_ using the command-line tools and this SQL::
CREATE DATABASE <dbname> CHARACTER SET utf8;
This ensures all tables and columns will use utf8 by default.
.. _create your database: http://dev.mysql.com/doc/refman/5.0/en/create-database.html
Connecting to the database
~~~~~~~~~~~~~~~~~~~~~~~~~~
Refer to the `settings documentation`_.
Connection settings are used in this order:
1. ``DATABASE_OPTIONS``
2. ``DATABASE_NAME``, ``DATABASE_USER``, ``DATABASE_PASSWORD``, ``DATABASE_HOST``,
``DATABASE_PORT``
3. MySQL option files.
In other words, if you set the name of the database in ``DATABASE_OPTIONS``,
this will take precedence over ``DATABASE_NAME``, which would override
anything in a `MySQL option file`_.
Here's a sample configuration which uses a MySQL option file::
# settings.py
DATABASE_ENGINE = "mysql"
DATABASE_OPTIONS = {
'read_default_file': '/path/to/my.cnf',
}
# my.cnf
[client]
database = DATABASE_NAME
user = DATABASE_USER
passwd = DATABASE_PASSWORD
default-character-set = utf8
There are several other MySQLdb connection options which may be useful, such
as ``ssl``, ``use_unicode``, ``init_command``, and ``sql_mode``; consult the
`MySQLdb documentation`_ for more details.
.. _settings documentation: http://www.djangoproject.com/documentation/settings/#database-engine
.. _MySQL option file: http://dev.mysql.com/doc/refman/5.0/en/option-files.html
.. _MySQLdb documentation: http://mysql-python.sourceforge.net/
Creating your tables
~~~~~~~~~~~~~~~~~~~~
When Django generates the schema, it doesn't specify a storage engine, so they
will be created with whatever default `storage engine`__ your database server
is configured for. The easiest solution is to set your database server's default
storage engine to the desired engine.
__ `storage engines`_
If you are using a hosting service and can't change your server's default
storage engine, you have a couple of options.
After the tables is created, all that is needed to convert it to a new storage
engine (such as InnoDB) is::
ALTER TABLE <tablename> ENGINE=INNODB;
With a lot of tables, this can be tedious.
Another option is to use the ``init_command`` option for MySQLdb prior to
creating your tables::
DATABASE_OPTIONS = {
...
"init_command": "SET storage_engine=INNODB",
...
}
This sets the default storage engine upon connecting to the database. After
your tables are set up and running in production, you should remove this
option.
Another method for changing the storage engine is described in
AlterModelOnSyncDB_.
.. _AlterModelOnSyncDB: http://code.djangoproject.com/wiki/AlterModelOnSyncDB

View File

@ -54,7 +54,7 @@ def pk_create(pk, klass, data):
def data_compare(testcase, pk, klass, data): def data_compare(testcase, pk, klass, data):
instance = klass.objects.get(id=pk) instance = klass.objects.get(id=pk)
testcase.assertEqual(data, instance.data, testcase.assertEqual(data, instance.data,
"Objects with PK=%d not equal; expected '%s', got '%s'" % (pk,data,instance.data)) "Objects with PK=%d not equal; expected '%s' (%s), got '%s' (%s)" % (pk,data, type(data), instance.data, type(instance.data)))
def fk_compare(testcase, pk, klass, data): def fk_compare(testcase, pk, klass, data):
instance = klass.objects.get(id=pk) instance = klass.objects.get(id=pk)