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-rw-r--r--doc/build/changelog/changelog_10.rst19
-rw-r--r--doc/build/changelog/migration_10.rst23
-rw-r--r--lib/sqlalchemy/dialects/mysql/base.py88
-rw-r--r--test/dialect/mysql/test_reflection.py55
-rw-r--r--test/dialect/mysql/test_types.py107
5 files changed, 215 insertions, 77 deletions
diff --git a/doc/build/changelog/changelog_10.rst b/doc/build/changelog/changelog_10.rst
index 89ef86844..ca0ae4d52 100644
--- a/doc/build/changelog/changelog_10.rst
+++ b/doc/build/changelog/changelog_10.rst
@@ -1,4 +1,5 @@
+
==============
1.0 Changelog
==============
@@ -23,6 +24,24 @@
on compatibility concerns, see :doc:`/changelog/migration_10`.
.. change::
+ :tags: feature, mysql
+ :tickets: 3155
+
+ The MySQL dialect now renders TIMESTAMP with NULL / NOT NULL in
+ all cases, so that MySQL 5.6.6 with the
+ ``explicit_defaults_for_timestamp`` flag enabled will
+ will allow TIMESTAMP to continue to work as expected when
+ ``nullable=False``. Existing applications are unaffected as
+ SQLAlchemy has always emitted NULL for a TIMESTAMP column that
+ is ``nullable=True``.
+
+ .. seealso::
+
+ :ref:`change_3155`
+
+ :ref:`mysql_timestamp_null`
+
+ .. change::
:tags: bug, schema
:tickets: 3299, 3067
diff --git a/doc/build/changelog/migration_10.rst b/doc/build/changelog/migration_10.rst
index 3ba0743f7..efb4b26e5 100644
--- a/doc/build/changelog/migration_10.rst
+++ b/doc/build/changelog/migration_10.rst
@@ -1817,6 +1817,29 @@ Support for the pypy psycopg2cffi dialect is added.
Dialect Improvements and Changes - MySQL
=============================================
+.. _change_3155:
+
+MySQL TIMESTAMP Type now renders NULL / NOT NULL in all cases
+--------------------------------------------------------------
+
+The MySQL dialect has always worked around MySQL's implicit NOT NULL
+default associated with TIMESTAMP columns by emitting NULL for
+such a type, if the column is set up with ``nullable=True``. However,
+MySQL 5.6.6 and above features a new flag
+`explicit_defaults_for_timestamp <http://dev.mysql.com/doc/refman/
+5.6/en/server-system-variables.html
+#sysvar_explicit_defaults_for_timestamp>`_ which repairs MySQL's non-standard
+behavior to make it behave like any other type; to accommodate this,
+SQLAlchemy now emits NULL/NOT NULL unconditionally for all TIMESTAMP
+columns.
+
+.. seealso::
+
+ :ref:`mysql_timestamp_null`
+
+:ticket:`3155`
+
+
.. _change_3283:
MySQL SET Type Overhauled to support empty sets, unicode, blank value handling
diff --git a/lib/sqlalchemy/dialects/mysql/base.py b/lib/sqlalchemy/dialects/mysql/base.py
index c8e33bfb2..cbb108f5e 100644
--- a/lib/sqlalchemy/dialects/mysql/base.py
+++ b/lib/sqlalchemy/dialects/mysql/base.py
@@ -370,10 +370,11 @@ collection.
TIMESTAMP Columns and NULL
--------------------------
-MySQL enforces that a column which specifies the TIMESTAMP datatype implicitly
-includes a default value of CURRENT_TIMESTAMP, even though this is not
-stated, and additionally sets the column as NOT NULL, the opposite behavior
-vs. that of all other datatypes::
+MySQL historically enforces that a column which specifies the
+TIMESTAMP datatype implicitly includes a default value of
+CURRENT_TIMESTAMP, even though this is not stated, and additionally
+sets the column as NOT NULL, the opposite behavior vs. that of all
+other datatypes::
mysql> CREATE TABLE ts_test (
-> a INTEGER,
@@ -400,22 +401,29 @@ with NOT NULL. But when the column is of type TIMESTAMP, an implicit
default of CURRENT_TIMESTAMP is generated which also coerces the column
to be a NOT NULL, even though we did not specify it as such.
-Therefore, the usual "NOT NULL" clause *does not apply* to a TIMESTAMP
-column; MySQL selects this implicitly. SQLAlchemy therefore does not render
-NOT NULL for a TIMESTAMP column on MySQL. However, it *does* render
-NULL when we specify nullable=True, or if we leave nullable absent, as it
-also defaults to True. This is to accommodate the essentially
-reverse behavior of the NULL flag for TIMESTAMP::
+This behavior of MySQL can be changed on the MySQL side using the
+`explicit_defaults_for_timestamp
+<http://dev.mysql.com/doc/refman/5.6/en/server-system-variables.html
+#sysvar_explicit_defaults_for_timestamp>`_ configuration flag introduced in
+MySQL 5.6. With this server setting enabled, TIMESTAMP columns behave like
+any other datatype on the MySQL side with regards to defaults and nullability.
- from sqlalchemy import MetaData, TIMESTAMP, Integer, Table, Column, text
+However, to accommodate the vast majority of MySQL databases that do not
+specify this new flag, SQLAlchemy emits the "NULL" specifier explicitly with
+any TIMESTAMP column that does not specify ``nullable=False``. In order
+to accommodate newer databases that specify ``explicit_defaults_for_timestamp``,
+SQLAlchemy also emits NOT NULL for TIMESTAMP columns that do specify
+``nullable=False``. The following example illustrates::
+
+ from sqlalchemy import MetaData, Integer, Table, Column, text
+ from sqlalchemy.dialects.mysql import TIMESTAMP
m = MetaData()
t = Table('ts_test', m,
Column('a', Integer),
Column('b', Integer, nullable=False),
Column('c', TIMESTAMP),
- Column('d', TIMESTAMP, nullable=False),
- Column('e', TIMESTAMP, nullable=True)
+ Column('d', TIMESTAMP, nullable=False)
)
@@ -423,35 +431,19 @@ reverse behavior of the NULL flag for TIMESTAMP::
e = create_engine("mysql://scott:tiger@localhost/test", echo=True)
m.create_all(e)
-In the output, we can see that the TIMESTAMP column receives a different
-treatment for NULL / NOT NULL vs. that of the INTEGER::
+output::
CREATE TABLE ts_test (
a INTEGER,
b INTEGER NOT NULL,
c TIMESTAMP NULL,
- d TIMESTAMP,
- e TIMESTAMP NULL
+ d TIMESTAMP NOT NULL
)
-MySQL above receives the NULL/NOT NULL constraint as is stated in our
-original :class:`.Table`::
-
- mysql> SHOW CREATE TABLE ts_test;
- +---------+---------------------------
- | Table | Create Table
- +---------+---------------------------
- | ts_test | CREATE TABLE `ts_test` (
- `a` int(11) DEFAULT NULL,
- `b` int(11) NOT NULL,
- `c` timestamp NULL DEFAULT NULL,
- `d` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
- `e` timestamp NULL DEFAULT NULL
- ) ENGINE=MyISAM DEFAULT CHARSET=latin1
-
-Be sure to always favor the ``SHOW CREATE TABLE`` output over the
-SQLAlchemy-emitted DDL when checking table definitions, as MySQL's
-rules can be hard to predict.
+.. versionchanged:: 1.0.0 - SQLAlchemy now renders NULL or NOT NULL in all
+ cases for TIMESTAMP columns, to accommodate
+ ``explicit_defaults_for_timestamp``. Prior to this version, it will
+ not render "NOT NULL" for a TIMESTAMP column that is ``nullable=False``.
"""
@@ -1865,19 +1857,20 @@ class MySQLDDLCompiler(compiler.DDLCompiler):
column.type, type_expression=column)
]
- default = self.get_column_default_string(column)
- if default is not None:
- colspec.append('DEFAULT ' + default)
-
is_timestamp = isinstance(column.type, sqltypes.TIMESTAMP)
- if not column.nullable and not is_timestamp:
+
+ if not column.nullable:
colspec.append('NOT NULL')
# see: http://docs.sqlalchemy.org/en/latest/dialects/
# mysql.html#mysql_timestamp_null
- elif column.nullable and is_timestamp and default is None:
+ elif column.nullable and is_timestamp:
colspec.append('NULL')
+ default = self.get_column_default_string(column)
+ if default is not None:
+ colspec.append('DEFAULT ' + default)
+
if column is column.table._autoincrement_column and \
column.server_default is None:
colspec.append('AUTO_INCREMENT')
@@ -3007,8 +3000,7 @@ class MySQLTableDefinitionParser(object):
if not spec['full']:
util.warn("Incomplete reflection of column definition %r" % line)
- name, type_, args, notnull = \
- spec['name'], spec['coltype'], spec['arg'], spec['notnull']
+ name, type_, args = spec['name'], spec['coltype'], spec['arg']
try:
col_type = self.dialect.ischema_names[type_]
@@ -3033,7 +3025,6 @@ class MySQLTableDefinitionParser(object):
for kw in ('charset', 'collate'):
if spec.get(kw, False):
type_kw[kw] = spec[kw]
-
if issubclass(col_type, _EnumeratedValues):
type_args = _EnumeratedValues._strip_values(type_args)
@@ -3042,11 +3033,12 @@ class MySQLTableDefinitionParser(object):
type_instance = col_type(*type_args, **type_kw)
- col_args, col_kw = [], {}
+ col_kw = {}
# NOT NULL
col_kw['nullable'] = True
- if spec.get('notnull', False):
+ # this can be "NULL" in the case of TIMESTAMP
+ if spec.get('notnull', False) == 'NOT NULL':
col_kw['nullable'] = False
# AUTO_INCREMENT
@@ -3165,7 +3157,7 @@ class MySQLTableDefinitionParser(object):
r'(?: +(?P<zerofill>ZEROFILL))?'
r'(?: +CHARACTER SET +(?P<charset>[\w_]+))?'
r'(?: +COLLATE +(?P<collate>[\w_]+))?'
- r'(?: +(?P<notnull>NOT NULL))?'
+ r'(?: +(?P<notnull>(?:NOT )?NULL))?'
r'(?: +DEFAULT +(?P<default>'
r'(?:NULL|\x27(?:\x27\x27|[^\x27])*\x27|\w+'
r'(?: +ON UPDATE \w+)?)'
@@ -3185,7 +3177,7 @@ class MySQLTableDefinitionParser(object):
r'%(iq)s(?P<name>(?:%(esc_fq)s|[^%(fq)s])+)%(fq)s +'
r'(?P<coltype>\w+)'
r'(?:\((?P<arg>(?:\d+|\d+,\d+|\x27(?:\x27\x27|[^\x27])+\x27))\))?'
- r'.*?(?P<notnull>NOT NULL)?'
+ r'.*?(?P<notnull>(?:NOT )NULL)?'
% quotes
)
diff --git a/test/dialect/mysql/test_reflection.py b/test/dialect/mysql/test_reflection.py
index 99733e397..957a7eb21 100644
--- a/test/dialect/mysql/test_reflection.py
+++ b/test/dialect/mysql/test_reflection.py
@@ -7,6 +7,7 @@ from sqlalchemy.dialects.mysql import base as mysql
from sqlalchemy.testing import fixtures, AssertsExecutionResults
from sqlalchemy import testing
+
class ReflectionTest(fixtures.TestBase, AssertsExecutionResults):
__only_on__ = 'mysql'
@@ -23,13 +24,12 @@ class ReflectionTest(fixtures.TestBase, AssertsExecutionResults):
DefaultClause(''), nullable=False),
Column('c2', String(10), DefaultClause('0')),
Column('c3', String(10), DefaultClause('abc')),
- Column('c4', TIMESTAMP, DefaultClause('2009-04-05 12:00:00'
- )),
+ Column('c4', TIMESTAMP, DefaultClause('2009-04-05 12:00:00')),
Column('c5', TIMESTAMP),
Column('c6', TIMESTAMP,
DefaultClause(sql.text("CURRENT_TIMESTAMP "
"ON UPDATE CURRENT_TIMESTAMP"))),
- )
+ )
def_table.create()
try:
reflected = Table('mysql_def', MetaData(testing.db),
@@ -284,6 +284,55 @@ class ReflectionTest(fixtures.TestBase, AssertsExecutionResults):
self.assert_('TABLES' in view_names)
@testing.provide_metadata
+ def test_nullable_reflection(self):
+ """test reflection of NULL/NOT NULL, in particular with TIMESTAMP
+ defaults where MySQL is inconsistent in how it reports CREATE TABLE.
+
+ """
+ meta = self.metadata
+ Table('nn_t', meta)
+ testing.db.execute("""
+ CREATE TABLE nn_t (
+ x INTEGER NULL,
+ y INTEGER NOT NULL,
+ z INTEGER,
+ q TIMESTAMP NULL,
+ p TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP,
+ r TIMESTAMP NOT NULL,
+ s TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+ t TIMESTAMP,
+ u TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+ )
+ """)
+ eq_(
+ [
+ {
+ "name": d['name'],
+ "nullable": d['nullable'],
+ "default": d['default'],
+ }
+ for d in
+ inspect(testing.db).get_columns('nn_t')
+ ],
+ [
+ {'name': 'x', 'nullable': True, 'default': None},
+ {'name': 'y', 'nullable': False, 'default': None},
+ {'name': 'z', 'nullable': True, 'default': None},
+ {'name': 'q', 'nullable': True, 'default': None},
+ {'name': 'p', 'nullable': True,
+ 'default': 'CURRENT_TIMESTAMP'},
+ {'name': 'r', 'nullable': False,
+ 'default': "'0000-00-00 00:00:00'"},
+ {'name': 's', 'nullable': False,
+ 'default': 'CURRENT_TIMESTAMP'},
+ {'name': 't', 'nullable': False,
+ 'default': "'0000-00-00 00:00:00'"},
+ {'name': 'u', 'nullable': False,
+ 'default': 'CURRENT_TIMESTAMP'},
+ ]
+ )
+
+ @testing.provide_metadata
def test_reflection_with_unique_constraint(self):
insp = inspect(testing.db)
diff --git a/test/dialect/mysql/test_types.py b/test/dialect/mysql/test_types.py
index 13425dc10..7c279ffbf 100644
--- a/test/dialect/mysql/test_types.py
+++ b/test/dialect/mysql/test_types.py
@@ -11,6 +11,7 @@ from sqlalchemy import testing
import datetime
import decimal
+
class TypesTest(fixtures.TestBase, AssertsExecutionResults, AssertsCompiledSQL):
"Test MySQL column types"
@@ -416,29 +417,66 @@ class TypesTest(fixtures.TestBase, AssertsExecutionResults, AssertsCompiledSQL):
"""Exercise funky TIMESTAMP default syntax when used in columns."""
columns = [
- ([TIMESTAMP],
+ ([TIMESTAMP], {},
'TIMESTAMP NULL'),
- ([mysql.MSTimeStamp],
+
+ ([mysql.MSTimeStamp], {},
'TIMESTAMP NULL'),
+
+ ([mysql.MSTimeStamp(),
+ DefaultClause(sql.text('CURRENT_TIMESTAMP'))],
+ {},
+ "TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP"),
+
([mysql.MSTimeStamp,
DefaultClause(sql.text('CURRENT_TIMESTAMP'))],
- "TIMESTAMP DEFAULT CURRENT_TIMESTAMP"),
+ {'nullable': False},
+ "TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP"),
+
([mysql.MSTimeStamp,
DefaultClause(sql.text("'1999-09-09 09:09:09'"))],
- "TIMESTAMP DEFAULT '1999-09-09 09:09:09'"),
+ {'nullable': False},
+ "TIMESTAMP NOT NULL DEFAULT '1999-09-09 09:09:09'"),
+
+ ([mysql.MSTimeStamp(),
+ DefaultClause(sql.text("'1999-09-09 09:09:09'"))],
+ {},
+ "TIMESTAMP NULL DEFAULT '1999-09-09 09:09:09'"),
+
+ ([mysql.MSTimeStamp(),
+ DefaultClause(sql.text(
+ "'1999-09-09 09:09:09' "
+ "ON UPDATE CURRENT_TIMESTAMP"))],
+ {},
+ "TIMESTAMP NULL DEFAULT '1999-09-09 09:09:09' "
+ "ON UPDATE CURRENT_TIMESTAMP"),
+
([mysql.MSTimeStamp,
- DefaultClause(sql.text("'1999-09-09 09:09:09' "
- "ON UPDATE CURRENT_TIMESTAMP"))],
- "TIMESTAMP DEFAULT '1999-09-09 09:09:09' "
+ DefaultClause(sql.text(
+ "'1999-09-09 09:09:09' "
+ "ON UPDATE CURRENT_TIMESTAMP"))],
+ {'nullable': False},
+ "TIMESTAMP NOT NULL DEFAULT '1999-09-09 09:09:09' "
+ "ON UPDATE CURRENT_TIMESTAMP"),
+
+ ([mysql.MSTimeStamp(),
+ DefaultClause(sql.text(
+ "CURRENT_TIMESTAMP "
+ "ON UPDATE CURRENT_TIMESTAMP"))],
+ {},
+ "TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP "
"ON UPDATE CURRENT_TIMESTAMP"),
+
([mysql.MSTimeStamp,
- DefaultClause(sql.text("CURRENT_TIMESTAMP "
- "ON UPDATE CURRENT_TIMESTAMP"))],
- "TIMESTAMP DEFAULT CURRENT_TIMESTAMP "
+ DefaultClause(sql.text(
+ "CURRENT_TIMESTAMP "
+ "ON UPDATE CURRENT_TIMESTAMP"))],
+ {'nullable': False},
+ "TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP "
"ON UPDATE CURRENT_TIMESTAMP"),
- ]
- for spec, expected in columns:
- c = Column('t', *spec)
+ ]
+ for spec, kw, expected in columns:
+ c = Column('t', *spec, **kw)
Table('t', MetaData(), c)
self.assert_compile(
schema.CreateColumn(c),
@@ -448,19 +486,20 @@ class TypesTest(fixtures.TestBase, AssertsExecutionResults, AssertsCompiledSQL):
@testing.provide_metadata
def test_timestamp_nullable(self):
- ts_table = Table('mysql_timestamp', self.metadata,
- Column('t1', TIMESTAMP),
- Column('t2', TIMESTAMP, nullable=False),
- )
+ ts_table = Table(
+ 'mysql_timestamp', self.metadata,
+ Column('t1', TIMESTAMP),
+ Column('t2', TIMESTAMP, nullable=False),
+ mysql_engine='InnoDB'
+ )
self.metadata.create_all()
- now = testing.db.execute("select now()").scalar()
-
# TIMESTAMP without NULL inserts current time when passed
# NULL. when not passed, generates 0000-00-00 quite
# annoyingly.
- ts_table.insert().execute({'t1': now, 't2': None})
- ts_table.insert().execute({'t1': None, 't2': None})
+ # the flag http://dev.mysql.com/doc/refman/5.6/en/\
+ # server-system-variables.html#sysvar_explicit_defaults_for_timestamp
+ # changes this for 5.6 if set.
# normalize dates that are over the second boundary
def normalize(dt):
@@ -470,11 +509,27 @@ class TypesTest(fixtures.TestBase, AssertsExecutionResults, AssertsCompiledSQL):
return now
else:
return dt
- eq_(
- [tuple([normalize(dt) for dt in row])
- for row in ts_table.select().execute()],
- [(now, now), (None, now)]
- )
+
+ with testing.db.begin() as conn:
+ now = conn.scalar("select now()")
+
+ conn.execute(
+ ts_table.insert(), {'t1': now, 't2': None})
+ conn.execute(
+ ts_table.insert(), {'t1': None, 't2': None})
+ conn.execute(
+ ts_table.insert(), {'t2': None})
+
+ eq_(
+ [tuple([normalize(dt) for dt in row])
+ for row in conn.execute(ts_table.select())],
+ [
+ (now, now),
+ (None, now),
+ (None, now)
+ ]
+ )
+
def test_datetime_generic(self):
self.assert_compile(
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