Supported Versions and Features
-------------------------------
-SQLAlchemy supports 6 major MySQL versions: 3.23, 4.0, 4.1, 5.0, 5.1 and 6.0,
-with capabilities increasing with more modern servers.
-
-Versions 4.1 and higher support the basic SQL functionality that SQLAlchemy
-uses in the ORM and SQL expressions. These versions pass the applicable tests
-in the suite 100%. No heroic measures are taken to work around major missing
-SQL features- if your server version does not support sub-selects, for
+SQLAlchemy supports MySQL starting with version 4.1 through modern releases.
+However, no heroic measures are taken to work around major missing
+SQL features - if your server version does not support sub-selects, for
example, they won't work in SQLAlchemy either.
-Most available DBAPI drivers are supported; see below.
-
-===================================== ===============
-Feature Minimum Version
-===================================== ===============
-sqlalchemy.orm 4.1.1
-Table Reflection 3.23.x
-DDL Generation 4.1.1
-utf8/Full Unicode Connections 4.1.1
-Transactions 3.23.15
-Two-Phase Transactions 5.0.3
-Nested Transactions 5.0.3
-===================================== ===============
-
See the official MySQL documentation for detailed information about features
supported in any given server release.
-------------------
MySQL features an automatic connection close behavior, for connections that have
-been idle for eight hours or more. To circumvent having this issue, use the
+been idle for eight hours or more. To circumvent having this issue, use the
``pool_recycle`` option which controls the maximum age of any connection::
engine = create_engine('mysql+mysqldb://...', pool_recycle=3600)
Column('id', Integer, primary_key=True)
)
-SQL Mode
---------
-
-MySQL SQL modes are supported. Modes that enable ``ANSI_QUOTES`` (such as
-``ANSI``) require an engine option to modify SQLAlchemy's quoting style.
-When using an ANSI-quoting mode, supply ``use_ansiquotes=True`` when
-creating your ``Engine``::
-
- create_engine('mysql://localhost/test', use_ansiquotes=True)
-
-This is an engine-wide option and is not toggleable on a per-connection basis.
-SQLAlchemy does not presume to ``SET sql_mode`` for you with this option. For
-the best performance, set the quoting style server-wide in ``my.cnf`` or by
-supplying ``--sql-mode`` to ``mysqld``. You can also use a
-:class:`sqlalchemy.pool.Pool` listener hook to issue a ``SET SESSION
-sql_mode='...'`` on connect to configure each connection.
-
-If you do not specify ``use_ansiquotes``, the regular MySQL quoting style is
-used by default.
+Ansi Quoting Style
+------------------
-If you do issue a ``SET sql_mode`` through SQLAlchemy, the dialect must be
-updated if the quoting style is changed. Again, this change will affect all
-connections::
+MySQL features two varieties of identifier "quoting style", one using
+backticks and the other using quotes, e.g. ```some_identifier``` vs.
+``"some_identifier"``. All MySQL dialects detect which version
+is in use by checking the value of ``sql_mode`` when a connection is first
+established with a particular :class:`.Engine`. This quoting style comes
+into play when rendering table and column names as well as when reflecting
+existing database structures. The detection is entirely automatic and
+no special configuration is needed to use either quoting style.
- connection.execute('SET sql_mode="ansi"')
- connection.dialect.use_ansiquotes = True
+.. versionchanged:: 0.6 detection of ANSI quoting style is entirely automatic,
+ there's no longer any end-user ``create_engine()`` options in this regard.
MySQL SQL Extensions
--------------------
This is in contradiction to the default setting on most MySQL DBAPI drivers,
which is "number of rows actually modified/deleted". For this reason, the
SQLAlchemy MySQL dialects always set the ``constants.CLIENT.FOUND_ROWS`` flag,
-or whatever is equivalent for the DBAPI in use, on connect, unless the flag value
+or whatever is equivalent for the DBAPI in use, on connect, unless the flag value
is overridden using DBAPI-specific options
(such as ``client_flag`` for the MySQL-Python driver, ``found_rows`` for the
OurSQL driver).
table_opts = []
opts = dict(
(
- k[len(self.dialect.name)+1:].upper(),
+ k[len(self.dialect.name)+1:].upper(),
v
)
for k, v in table.kwargs.items()
arg = "'%s'" % arg.replace("\\", "\\\\").replace("'", "''")
if opt in ('DATA_DIRECTORY', 'INDEX_DIRECTORY',
- 'DEFAULT_CHARACTER_SET', 'CHARACTER_SET',
+ 'DEFAULT_CHARACTER_SET', 'CHARACTER_SET',
'DEFAULT_CHARSET',
'DEFAULT_COLLATE'):
opt = opt.replace('_', ' ')
quote = '"'
super(MySQLIdentifierPreparer, self).__init__(
- dialect,
- initial_quote=quote,
+ dialect,
+ initial_quote=quote,
escape_quote=quote)
def _quote_free_identifiers(self, *ids):
preparer = MySQLIdentifierPreparer
# default SQL compilation settings -
- # these are modified upon initialize(),
+ # these are modified upon initialize(),
# i.e. first connect
_backslash_escapes = True
_server_ansiquotes = False
return self._extract_error_code(e) in \
(2006, 2013, 2014, 2045, 2055)
elif isinstance(e, self.dbapi.InterfaceError):
- # if underlying connection is closed,
+ # if underlying connection is closed,
# this is the error you get
return "(0, '')" in str(e)
else:
def _parsed_state_or_create(self, connection, table_name, schema=None, **kw):
return self._setup_parser(
- connection,
- table_name,
- schema,
+ connection,
+ table_name,
+ schema,
info_cache=kw.get('info_cache', None)
)
def _tabledef_parser(self):
"""return the MySQLTableDefinitionParser, generate if needed.
- The deferred creation ensures that the dialect has
+ The deferred creation ensures that the dialect has
retrieved server version information first.
"""
row = self._compat_first(
connection.execute("SHOW VARIABLES LIKE 'sql_mode'"),
- charset=self._connection_charset)
+ charset=self._connection_charset)
if not row:
mode = ''
projects / thirdparty / sqlalchemy / sqlalchemy.git / commitdiff
