936 lines
34 KiB
Python
936 lines
34 KiB
Python
# sqlite/base.py
|
|
# Copyright (C) 2005-2013 the SQLAlchemy authors and contributors <see AUTHORS file>
|
|
#
|
|
# This module is part of SQLAlchemy and is released under
|
|
# the MIT License: http://www.opensource.org/licenses/mit-license.php
|
|
|
|
"""
|
|
.. dialect:: sqlite
|
|
:name: SQLite
|
|
|
|
|
|
Date and Time Types
|
|
-------------------
|
|
|
|
SQLite does not have built-in DATE, TIME, or DATETIME types, and pysqlite
|
|
does not provide out of the box functionality for translating values between
|
|
Python `datetime` objects and a SQLite-supported format. SQLAlchemy's own
|
|
:class:`~sqlalchemy.types.DateTime` and related types provide date formatting
|
|
and parsing functionality when SQlite is used. The implementation classes are
|
|
:class:`~.sqlite.DATETIME`, :class:`~.sqlite.DATE` and :class:`~.sqlite.TIME`.
|
|
These types represent dates and times as ISO formatted strings, which also
|
|
nicely support ordering. There's no reliance on typical "libc" internals
|
|
for these functions so historical dates are fully supported.
|
|
|
|
Auto Incrementing Behavior
|
|
--------------------------
|
|
|
|
Background on SQLite's autoincrement is at: http://sqlite.org/autoinc.html
|
|
|
|
Two things to note:
|
|
|
|
* The AUTOINCREMENT keyword is **not** required for SQLite tables to
|
|
generate primary key values automatically. AUTOINCREMENT only means that
|
|
the algorithm used to generate ROWID values should be slightly different.
|
|
* SQLite does **not** generate primary key (i.e. ROWID) values, even for
|
|
one column, if the table has a composite (i.e. multi-column) primary key.
|
|
This is regardless of the AUTOINCREMENT keyword being present or not.
|
|
|
|
To specifically render the AUTOINCREMENT keyword on the primary key
|
|
column when rendering DDL, add the flag ``sqlite_autoincrement=True``
|
|
to the Table construct::
|
|
|
|
Table('sometable', metadata,
|
|
Column('id', Integer, primary_key=True),
|
|
sqlite_autoincrement=True)
|
|
|
|
Transaction Isolation Level
|
|
---------------------------
|
|
|
|
:func:`.create_engine` accepts an ``isolation_level`` parameter which
|
|
results in the command ``PRAGMA read_uncommitted <level>`` being invoked for
|
|
every new connection. Valid values for this parameter are ``SERIALIZABLE``
|
|
and ``READ UNCOMMITTED`` corresponding to a value of 0 and 1, respectively.
|
|
See the section :ref:`pysqlite_serializable` for an important workaround
|
|
when using serializable isolation with Pysqlite.
|
|
|
|
Database Locking Behavior / Concurrency
|
|
---------------------------------------
|
|
|
|
Note that SQLite is not designed for a high level of concurrency. The
|
|
database itself, being a file, is locked completely during write operations
|
|
and within transactions, meaning exactly one connection has exclusive access
|
|
to the database during this period - all other connections will be blocked
|
|
during this time.
|
|
|
|
The Python DBAPI specification also calls for a connection model that is always
|
|
in a transaction; there is no BEGIN method, only commit and rollback. This
|
|
implies that a SQLite DBAPI driver would technically allow only serialized
|
|
access to a particular database file at all times. The pysqlite driver
|
|
attempts to ameliorate this by deferring the actual BEGIN statement until
|
|
the first DML (INSERT, UPDATE, or DELETE) is received within a
|
|
transaction. While this breaks serializable isolation, it at least delays
|
|
the exclusive locking inherent in SQLite's design.
|
|
|
|
SQLAlchemy's default mode of usage with the ORM is known
|
|
as "autocommit=False", which means the moment the :class:`.Session` begins to
|
|
be used, a transaction is begun. As the :class:`.Session` is used, the
|
|
autoflush feature, also on by default, will flush out pending changes to the
|
|
database before each query. The effect of this is that a :class:`.Session`
|
|
used in its default mode will often emit DML early on, long before the
|
|
transaction is actually committed. This again will have the effect of
|
|
serializing access to the SQLite database. If highly concurrent reads are
|
|
desired against the SQLite database, it is advised that the autoflush feature
|
|
be disabled, and potentially even that autocommit be re-enabled, which has
|
|
the effect of each SQL statement and flush committing changes immediately.
|
|
|
|
For more information on SQLite's lack of concurrency by design, please
|
|
see `Situations Where Another RDBMS May Work Better - High
|
|
Concurrency <http://www.sqlite.org/whentouse.html>`_ near the bottom of
|
|
the page.
|
|
|
|
.. _sqlite_foreign_keys:
|
|
|
|
Foreign Key Support
|
|
-------------------
|
|
|
|
SQLite supports FOREIGN KEY syntax when emitting CREATE statements for tables,
|
|
however by default these constraints have no effect on the operation
|
|
of the table.
|
|
|
|
Constraint checking on SQLite has three prerequisites:
|
|
|
|
* At least version 3.6.19 of SQLite must be in use
|
|
* The SQLite libary must be compiled *without* the SQLITE_OMIT_FOREIGN_KEY
|
|
or SQLITE_OMIT_TRIGGER symbols enabled.
|
|
* The ``PRAGMA foreign_keys = ON`` statement must be emitted on all connections
|
|
before use.
|
|
|
|
SQLAlchemy allows for the ``PRAGMA`` statement to be emitted automatically
|
|
for new connections through the usage of events::
|
|
|
|
from sqlalchemy.engine import Engine
|
|
from sqlalchemy import event
|
|
|
|
@event.listens_for(Engine, "connect")
|
|
def set_sqlite_pragma(dbapi_connection, connection_record):
|
|
cursor = dbapi_connection.cursor()
|
|
cursor.execute("PRAGMA foreign_keys=ON")
|
|
cursor.close()
|
|
|
|
.. seealso::
|
|
|
|
`SQLite Foreign Key Support <http://www.sqlite.org/foreignkeys.html>`_ -
|
|
on the SQLite web site.
|
|
|
|
:ref:`event_toplevel` - SQLAlchemy event API.
|
|
|
|
"""
|
|
|
|
import datetime
|
|
import re
|
|
|
|
from sqlalchemy import sql, exc
|
|
from sqlalchemy.engine import default, base, reflection
|
|
from sqlalchemy import types as sqltypes
|
|
from sqlalchemy import util
|
|
from sqlalchemy.sql import compiler
|
|
from sqlalchemy import processors
|
|
|
|
from sqlalchemy.types import BIGINT, BLOB, BOOLEAN, CHAR,\
|
|
DECIMAL, FLOAT, REAL, INTEGER, NUMERIC, SMALLINT, TEXT,\
|
|
TIMESTAMP, VARCHAR
|
|
|
|
|
|
class _DateTimeMixin(object):
|
|
_reg = None
|
|
_storage_format = None
|
|
|
|
def __init__(self, storage_format=None, regexp=None, **kw):
|
|
super(_DateTimeMixin, self).__init__(**kw)
|
|
if regexp is not None:
|
|
self._reg = re.compile(regexp)
|
|
if storage_format is not None:
|
|
self._storage_format = storage_format
|
|
|
|
def adapt(self, cls, **kw):
|
|
if self._storage_format:
|
|
kw["storage_format"] = self._storage_format
|
|
if self._reg:
|
|
kw["regexp"] = self._reg
|
|
return util.constructor_copy(self, cls, **kw)
|
|
|
|
class DATETIME(_DateTimeMixin, sqltypes.DateTime):
|
|
"""Represent a Python datetime object in SQLite using a string.
|
|
|
|
The default string storage format is::
|
|
|
|
"%(year)04d-%(month)02d-%(day)02d %(hour)02d:%(min)02d:%(second)02d.%(microsecond)06d"
|
|
|
|
e.g.::
|
|
|
|
2011-03-15 12:05:57.10558
|
|
|
|
The storage format can be customized to some degree using the
|
|
``storage_format`` and ``regexp`` parameters, such as::
|
|
|
|
import re
|
|
from sqlalchemy.dialects.sqlite import DATETIME
|
|
|
|
dt = DATETIME(
|
|
storage_format="%(year)04d/%(month)02d/%(day)02d %(hour)02d:%(min)02d:%(second)02d",
|
|
regexp=r"(\d+)/(\d+)/(\d+) (\d+)-(\d+)-(\d+)"
|
|
)
|
|
|
|
:param storage_format: format string which will be applied to the
|
|
dict with keys year, month, day, hour, minute, second, and microsecond.
|
|
|
|
:param regexp: regular expression which will be applied to
|
|
incoming result rows. If the regexp contains named groups, the
|
|
resulting match dict is applied to the Python datetime() constructor
|
|
as keyword arguments. Otherwise, if positional groups are used, the
|
|
the datetime() constructor is called with positional arguments via
|
|
``*map(int, match_obj.groups(0))``.
|
|
"""
|
|
|
|
_storage_format = (
|
|
"%(year)04d-%(month)02d-%(day)02d "
|
|
"%(hour)02d:%(minute)02d:%(second)02d.%(microsecond)06d"
|
|
)
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
truncate_microseconds = kwargs.pop('truncate_microseconds', False)
|
|
super(DATETIME, self).__init__(*args, **kwargs)
|
|
if truncate_microseconds:
|
|
assert 'storage_format' not in kwargs, "You can specify only "\
|
|
"one of truncate_microseconds or storage_format."
|
|
assert 'regexp' not in kwargs, "You can specify only one of "\
|
|
"truncate_microseconds or regexp."
|
|
self._storage_format = (
|
|
"%(year)04d-%(month)02d-%(day)02d "
|
|
"%(hour)02d:%(minute)02d:%(second)02d"
|
|
)
|
|
|
|
def bind_processor(self, dialect):
|
|
datetime_datetime = datetime.datetime
|
|
datetime_date = datetime.date
|
|
format = self._storage_format
|
|
|
|
def process(value):
|
|
if value is None:
|
|
return None
|
|
elif isinstance(value, datetime_datetime):
|
|
return format % {
|
|
'year': value.year,
|
|
'month': value.month,
|
|
'day': value.day,
|
|
'hour': value.hour,
|
|
'minute': value.minute,
|
|
'second': value.second,
|
|
'microsecond': value.microsecond,
|
|
}
|
|
elif isinstance(value, datetime_date):
|
|
return format % {
|
|
'year': value.year,
|
|
'month': value.month,
|
|
'day': value.day,
|
|
'hour': 0,
|
|
'minute': 0,
|
|
'second': 0,
|
|
'microsecond': 0,
|
|
}
|
|
else:
|
|
raise TypeError("SQLite DateTime type only accepts Python "
|
|
"datetime and date objects as input.")
|
|
return process
|
|
|
|
def result_processor(self, dialect, coltype):
|
|
if self._reg:
|
|
return processors.str_to_datetime_processor_factory(
|
|
self._reg, datetime.datetime)
|
|
else:
|
|
return processors.str_to_datetime
|
|
|
|
|
|
class DATE(_DateTimeMixin, sqltypes.Date):
|
|
"""Represent a Python date object in SQLite using a string.
|
|
|
|
The default string storage format is::
|
|
|
|
"%(year)04d-%(month)02d-%(day)02d"
|
|
|
|
e.g.::
|
|
|
|
2011-03-15
|
|
|
|
The storage format can be customized to some degree using the
|
|
``storage_format`` and ``regexp`` parameters, such as::
|
|
|
|
import re
|
|
from sqlalchemy.dialects.sqlite import DATE
|
|
|
|
d = DATE(
|
|
storage_format="%(month)02d/%(day)02d/%(year)04d",
|
|
regexp=re.compile("(?P<month>\d+)/(?P<day>\d+)/(?P<year>\d+)")
|
|
)
|
|
|
|
:param storage_format: format string which will be applied to the
|
|
dict with keys year, month, and day.
|
|
|
|
:param regexp: regular expression which will be applied to
|
|
incoming result rows. If the regexp contains named groups, the
|
|
resulting match dict is applied to the Python date() constructor
|
|
as keyword arguments. Otherwise, if positional groups are used, the
|
|
the date() constructor is called with positional arguments via
|
|
``*map(int, match_obj.groups(0))``.
|
|
"""
|
|
|
|
_storage_format = "%(year)04d-%(month)02d-%(day)02d"
|
|
|
|
def bind_processor(self, dialect):
|
|
datetime_date = datetime.date
|
|
format = self._storage_format
|
|
|
|
def process(value):
|
|
if value is None:
|
|
return None
|
|
elif isinstance(value, datetime_date):
|
|
return format % {
|
|
'year': value.year,
|
|
'month': value.month,
|
|
'day': value.day,
|
|
}
|
|
else:
|
|
raise TypeError("SQLite Date type only accepts Python "
|
|
"date objects as input.")
|
|
return process
|
|
|
|
def result_processor(self, dialect, coltype):
|
|
if self._reg:
|
|
return processors.str_to_datetime_processor_factory(
|
|
self._reg, datetime.date)
|
|
else:
|
|
return processors.str_to_date
|
|
|
|
|
|
class TIME(_DateTimeMixin, sqltypes.Time):
|
|
"""Represent a Python time object in SQLite using a string.
|
|
|
|
The default string storage format is::
|
|
|
|
"%(hour)02d:%(minute)02d:%(second)02d.%(microsecond)06d"
|
|
|
|
e.g.::
|
|
|
|
12:05:57.10558
|
|
|
|
The storage format can be customized to some degree using the
|
|
``storage_format`` and ``regexp`` parameters, such as::
|
|
|
|
import re
|
|
from sqlalchemy.dialects.sqlite import TIME
|
|
|
|
t = TIME(
|
|
storage_format="%(hour)02d-%(minute)02d-%(second)02d-%(microsecond)06d",
|
|
regexp=re.compile("(\d+)-(\d+)-(\d+)-(?:-(\d+))?")
|
|
)
|
|
|
|
:param storage_format: format string which will be applied to the
|
|
dict with keys hour, minute, second, and microsecond.
|
|
|
|
:param regexp: regular expression which will be applied to
|
|
incoming result rows. If the regexp contains named groups, the
|
|
resulting match dict is applied to the Python time() constructor
|
|
as keyword arguments. Otherwise, if positional groups are used, the
|
|
the time() constructor is called with positional arguments via
|
|
``*map(int, match_obj.groups(0))``.
|
|
"""
|
|
|
|
_storage_format = "%(hour)02d:%(minute)02d:%(second)02d.%(microsecond)06d"
|
|
|
|
def __init__(self, *args, **kwargs):
|
|
truncate_microseconds = kwargs.pop('truncate_microseconds', False)
|
|
super(TIME, self).__init__(*args, **kwargs)
|
|
if truncate_microseconds:
|
|
assert 'storage_format' not in kwargs, "You can specify only "\
|
|
"one of truncate_microseconds or storage_format."
|
|
assert 'regexp' not in kwargs, "You can specify only one of "\
|
|
"truncate_microseconds or regexp."
|
|
self._storage_format = "%(hour)02d:%(minute)02d:%(second)02d"
|
|
|
|
def bind_processor(self, dialect):
|
|
datetime_time = datetime.time
|
|
format = self._storage_format
|
|
|
|
def process(value):
|
|
if value is None:
|
|
return None
|
|
elif isinstance(value, datetime_time):
|
|
return format % {
|
|
'hour': value.hour,
|
|
'minute': value.minute,
|
|
'second': value.second,
|
|
'microsecond': value.microsecond,
|
|
}
|
|
else:
|
|
raise TypeError("SQLite Time type only accepts Python "
|
|
"time objects as input.")
|
|
return process
|
|
|
|
def result_processor(self, dialect, coltype):
|
|
if self._reg:
|
|
return processors.str_to_datetime_processor_factory(
|
|
self._reg, datetime.time)
|
|
else:
|
|
return processors.str_to_time
|
|
|
|
colspecs = {
|
|
sqltypes.Date: DATE,
|
|
sqltypes.DateTime: DATETIME,
|
|
sqltypes.Time: TIME,
|
|
}
|
|
|
|
ischema_names = {
|
|
'BIGINT': sqltypes.BIGINT,
|
|
'BLOB': sqltypes.BLOB,
|
|
'BOOL': sqltypes.BOOLEAN,
|
|
'BOOLEAN': sqltypes.BOOLEAN,
|
|
'CHAR': sqltypes.CHAR,
|
|
'DATE': sqltypes.DATE,
|
|
'DATETIME': sqltypes.DATETIME,
|
|
'DECIMAL': sqltypes.DECIMAL,
|
|
'FLOAT': sqltypes.FLOAT,
|
|
'INT': sqltypes.INTEGER,
|
|
'INTEGER': sqltypes.INTEGER,
|
|
'NUMERIC': sqltypes.NUMERIC,
|
|
'REAL': sqltypes.REAL,
|
|
'SMALLINT': sqltypes.SMALLINT,
|
|
'TEXT': sqltypes.TEXT,
|
|
'TIME': sqltypes.TIME,
|
|
'TIMESTAMP': sqltypes.TIMESTAMP,
|
|
'VARCHAR': sqltypes.VARCHAR,
|
|
'NVARCHAR': sqltypes.NVARCHAR,
|
|
'NCHAR': sqltypes.NCHAR,
|
|
}
|
|
|
|
|
|
class SQLiteCompiler(compiler.SQLCompiler):
|
|
extract_map = util.update_copy(
|
|
compiler.SQLCompiler.extract_map,
|
|
{
|
|
'month': '%m',
|
|
'day': '%d',
|
|
'year': '%Y',
|
|
'second': '%S',
|
|
'hour': '%H',
|
|
'doy': '%j',
|
|
'minute': '%M',
|
|
'epoch': '%s',
|
|
'dow': '%w',
|
|
'week': '%W'
|
|
})
|
|
|
|
def visit_now_func(self, fn, **kw):
|
|
return "CURRENT_TIMESTAMP"
|
|
|
|
def visit_localtimestamp_func(self, func, **kw):
|
|
return 'DATETIME(CURRENT_TIMESTAMP, "localtime")'
|
|
|
|
def visit_true(self, expr, **kw):
|
|
return '1'
|
|
|
|
def visit_false(self, expr, **kw):
|
|
return '0'
|
|
|
|
def visit_char_length_func(self, fn, **kw):
|
|
return "length%s" % self.function_argspec(fn)
|
|
|
|
def visit_cast(self, cast, **kwargs):
|
|
if self.dialect.supports_cast:
|
|
return super(SQLiteCompiler, self).visit_cast(cast)
|
|
else:
|
|
return self.process(cast.clause)
|
|
|
|
def visit_extract(self, extract, **kw):
|
|
try:
|
|
return "CAST(STRFTIME('%s', %s) AS INTEGER)" % (
|
|
self.extract_map[extract.field],
|
|
self.process(extract.expr, **kw)
|
|
)
|
|
except KeyError:
|
|
raise exc.CompileError(
|
|
"%s is not a valid extract argument." % extract.field)
|
|
|
|
def limit_clause(self, select):
|
|
text = ""
|
|
if select._limit is not None:
|
|
text += "\n LIMIT " + self.process(sql.literal(select._limit))
|
|
if select._offset is not None:
|
|
if select._limit is None:
|
|
text += "\n LIMIT " + self.process(sql.literal(-1))
|
|
text += " OFFSET " + self.process(sql.literal(select._offset))
|
|
else:
|
|
text += " OFFSET " + self.process(sql.literal(0))
|
|
return text
|
|
|
|
def for_update_clause(self, select):
|
|
# sqlite has no "FOR UPDATE" AFAICT
|
|
return ''
|
|
|
|
|
|
class SQLiteDDLCompiler(compiler.DDLCompiler):
|
|
|
|
def get_column_specification(self, column, **kwargs):
|
|
coltype = self.dialect.type_compiler.process(column.type)
|
|
colspec = self.preparer.format_column(column) + " " + coltype
|
|
default = self.get_column_default_string(column)
|
|
if default is not None:
|
|
colspec += " DEFAULT " + default
|
|
|
|
if not column.nullable:
|
|
colspec += " NOT NULL"
|
|
|
|
if (column.primary_key and
|
|
column.table.kwargs.get('sqlite_autoincrement', False) and
|
|
len(column.table.primary_key.columns) == 1 and
|
|
issubclass(column.type._type_affinity, sqltypes.Integer) and
|
|
not column.foreign_keys):
|
|
colspec += " PRIMARY KEY AUTOINCREMENT"
|
|
|
|
return colspec
|
|
|
|
def visit_primary_key_constraint(self, constraint):
|
|
# for columns with sqlite_autoincrement=True,
|
|
# the PRIMARY KEY constraint can only be inline
|
|
# with the column itself.
|
|
if len(constraint.columns) == 1:
|
|
c = list(constraint)[0]
|
|
if c.primary_key and \
|
|
c.table.kwargs.get('sqlite_autoincrement', False) and \
|
|
issubclass(c.type._type_affinity, sqltypes.Integer) and \
|
|
not c.foreign_keys:
|
|
return None
|
|
|
|
return super(SQLiteDDLCompiler, self).\
|
|
visit_primary_key_constraint(constraint)
|
|
|
|
def visit_foreign_key_constraint(self, constraint):
|
|
|
|
local_table = constraint._elements.values()[0].parent.table
|
|
remote_table = list(constraint._elements.values())[0].column.table
|
|
|
|
if local_table.schema != remote_table.schema:
|
|
return None
|
|
else:
|
|
return super(SQLiteDDLCompiler, self).visit_foreign_key_constraint(constraint)
|
|
|
|
def define_constraint_remote_table(self, constraint, table, preparer):
|
|
"""Format the remote table clause of a CREATE CONSTRAINT clause."""
|
|
|
|
return preparer.format_table(table, use_schema=False)
|
|
|
|
def visit_create_index(self, create):
|
|
return super(SQLiteDDLCompiler, self).\
|
|
visit_create_index(create, include_table_schema=False)
|
|
|
|
|
|
class SQLiteTypeCompiler(compiler.GenericTypeCompiler):
|
|
def visit_large_binary(self, type_):
|
|
return self.visit_BLOB(type_)
|
|
|
|
|
|
class SQLiteIdentifierPreparer(compiler.IdentifierPreparer):
|
|
reserved_words = set([
|
|
'add', 'after', 'all', 'alter', 'analyze', 'and', 'as', 'asc',
|
|
'attach', 'autoincrement', 'before', 'begin', 'between', 'by',
|
|
'cascade', 'case', 'cast', 'check', 'collate', 'column', 'commit',
|
|
'conflict', 'constraint', 'create', 'cross', 'current_date',
|
|
'current_time', 'current_timestamp', 'database', 'default',
|
|
'deferrable', 'deferred', 'delete', 'desc', 'detach', 'distinct',
|
|
'drop', 'each', 'else', 'end', 'escape', 'except', 'exclusive',
|
|
'explain', 'false', 'fail', 'for', 'foreign', 'from', 'full', 'glob',
|
|
'group', 'having', 'if', 'ignore', 'immediate', 'in', 'index',
|
|
'indexed', 'initially', 'inner', 'insert', 'instead', 'intersect',
|
|
'into', 'is', 'isnull', 'join', 'key', 'left', 'like', 'limit',
|
|
'match', 'natural', 'not', 'notnull', 'null', 'of', 'offset', 'on',
|
|
'or', 'order', 'outer', 'plan', 'pragma', 'primary', 'query',
|
|
'raise', 'references', 'reindex', 'rename', 'replace', 'restrict',
|
|
'right', 'rollback', 'row', 'select', 'set', 'table', 'temp',
|
|
'temporary', 'then', 'to', 'transaction', 'trigger', 'true', 'union',
|
|
'unique', 'update', 'using', 'vacuum', 'values', 'view', 'virtual',
|
|
'when', 'where',
|
|
])
|
|
|
|
def format_index(self, index, use_schema=True, name=None):
|
|
"""Prepare a quoted index and schema name."""
|
|
|
|
if name is None:
|
|
name = index.name
|
|
result = self.quote(name, index.quote)
|
|
if (not self.omit_schema and
|
|
use_schema and
|
|
getattr(index.table, "schema", None)):
|
|
result = self.quote_schema(
|
|
index.table.schema, index.table.quote_schema) + "." + result
|
|
return result
|
|
|
|
|
|
class SQLiteExecutionContext(default.DefaultExecutionContext):
|
|
@util.memoized_property
|
|
def _preserve_raw_colnames(self):
|
|
return self.execution_options.get("sqlite_raw_colnames", False)
|
|
|
|
def _translate_colname(self, colname):
|
|
# adjust for dotted column names. SQLite
|
|
# in the case of UNION may store col names as
|
|
# "tablename.colname"
|
|
# in cursor.description
|
|
if not self._preserve_raw_colnames and "." in colname:
|
|
return colname.split(".")[1], colname
|
|
else:
|
|
return colname, None
|
|
|
|
|
|
class SQLiteDialect(default.DefaultDialect):
|
|
name = 'sqlite'
|
|
supports_alter = False
|
|
supports_unicode_statements = True
|
|
supports_unicode_binds = True
|
|
supports_default_values = True
|
|
supports_empty_insert = False
|
|
supports_cast = True
|
|
supports_multivalues_insert = True
|
|
|
|
default_paramstyle = 'qmark'
|
|
execution_ctx_cls = SQLiteExecutionContext
|
|
statement_compiler = SQLiteCompiler
|
|
ddl_compiler = SQLiteDDLCompiler
|
|
type_compiler = SQLiteTypeCompiler
|
|
preparer = SQLiteIdentifierPreparer
|
|
ischema_names = ischema_names
|
|
colspecs = colspecs
|
|
isolation_level = None
|
|
|
|
supports_cast = True
|
|
supports_default_values = True
|
|
|
|
_broken_fk_pragma_quotes = False
|
|
|
|
def __init__(self, isolation_level=None, native_datetime=False, **kwargs):
|
|
default.DefaultDialect.__init__(self, **kwargs)
|
|
self.isolation_level = isolation_level
|
|
|
|
# this flag used by pysqlite dialect, and perhaps others in the
|
|
# future, to indicate the driver is handling date/timestamp
|
|
# conversions (and perhaps datetime/time as well on some
|
|
# hypothetical driver ?)
|
|
self.native_datetime = native_datetime
|
|
|
|
if self.dbapi is not None:
|
|
self.supports_default_values = \
|
|
self.dbapi.sqlite_version_info >= (3, 3, 8)
|
|
self.supports_cast = \
|
|
self.dbapi.sqlite_version_info >= (3, 2, 3)
|
|
self.supports_multivalues_insert = \
|
|
self.dbapi.sqlite_version_info >= (3, 7, 11)
|
|
# http://www.sqlite.org/releaselog/3_7_11.html
|
|
|
|
# see http://www.sqlalchemy.org/trac/ticket/2568
|
|
# as well as http://www.sqlite.org/src/info/600482d161
|
|
self._broken_fk_pragma_quotes = \
|
|
self.dbapi.sqlite_version_info < (3, 6, 14)
|
|
|
|
|
|
_isolation_lookup = {
|
|
'READ UNCOMMITTED': 1,
|
|
'SERIALIZABLE': 0
|
|
}
|
|
|
|
def set_isolation_level(self, connection, level):
|
|
try:
|
|
isolation_level = self._isolation_lookup[level.replace('_', ' ')]
|
|
except KeyError:
|
|
raise exc.ArgumentError(
|
|
"Invalid value '%s' for isolation_level. "
|
|
"Valid isolation levels for %s are %s" %
|
|
(level, self.name, ", ".join(self._isolation_lookup))
|
|
)
|
|
cursor = connection.cursor()
|
|
cursor.execute("PRAGMA read_uncommitted = %d" % isolation_level)
|
|
cursor.close()
|
|
|
|
def get_isolation_level(self, connection):
|
|
cursor = connection.cursor()
|
|
cursor.execute('PRAGMA read_uncommitted')
|
|
res = cursor.fetchone()
|
|
if res:
|
|
value = res[0]
|
|
else:
|
|
# http://www.sqlite.org/changes.html#version_3_3_3
|
|
# "Optional READ UNCOMMITTED isolation (instead of the
|
|
# default isolation level of SERIALIZABLE) and
|
|
# table level locking when database connections
|
|
# share a common cache.""
|
|
# pre-SQLite 3.3.0 default to 0
|
|
value = 0
|
|
cursor.close()
|
|
if value == 0:
|
|
return "SERIALIZABLE"
|
|
elif value == 1:
|
|
return "READ UNCOMMITTED"
|
|
else:
|
|
assert False, "Unknown isolation level %s" % value
|
|
|
|
def on_connect(self):
|
|
if self.isolation_level is not None:
|
|
def connect(conn):
|
|
self.set_isolation_level(conn, self.isolation_level)
|
|
return connect
|
|
else:
|
|
return None
|
|
|
|
@reflection.cache
|
|
def get_table_names(self, connection, schema=None, **kw):
|
|
if schema is not None:
|
|
qschema = self.identifier_preparer.quote_identifier(schema)
|
|
master = '%s.sqlite_master' % qschema
|
|
s = ("SELECT name FROM %s "
|
|
"WHERE type='table' ORDER BY name") % (master,)
|
|
rs = connection.execute(s)
|
|
else:
|
|
try:
|
|
s = ("SELECT name FROM "
|
|
" (SELECT * FROM sqlite_master UNION ALL "
|
|
" SELECT * FROM sqlite_temp_master) "
|
|
"WHERE type='table' ORDER BY name")
|
|
rs = connection.execute(s)
|
|
except exc.DBAPIError:
|
|
s = ("SELECT name FROM sqlite_master "
|
|
"WHERE type='table' ORDER BY name")
|
|
rs = connection.execute(s)
|
|
|
|
return [row[0] for row in rs]
|
|
|
|
def has_table(self, connection, table_name, schema=None):
|
|
quote = self.identifier_preparer.quote_identifier
|
|
if schema is not None:
|
|
pragma = "PRAGMA %s." % quote(schema)
|
|
else:
|
|
pragma = "PRAGMA "
|
|
qtable = quote(table_name)
|
|
statement = "%stable_info(%s)" % (pragma, qtable)
|
|
cursor = _pragma_cursor(connection.execute(statement))
|
|
row = cursor.fetchone()
|
|
|
|
# consume remaining rows, to work around
|
|
# http://www.sqlite.org/cvstrac/tktview?tn=1884
|
|
while not cursor.closed and cursor.fetchone() is not None:
|
|
pass
|
|
|
|
return (row is not None)
|
|
|
|
@reflection.cache
|
|
def get_view_names(self, connection, schema=None, **kw):
|
|
if schema is not None:
|
|
qschema = self.identifier_preparer.quote_identifier(schema)
|
|
master = '%s.sqlite_master' % qschema
|
|
s = ("SELECT name FROM %s "
|
|
"WHERE type='view' ORDER BY name") % (master,)
|
|
rs = connection.execute(s)
|
|
else:
|
|
try:
|
|
s = ("SELECT name FROM "
|
|
" (SELECT * FROM sqlite_master UNION ALL "
|
|
" SELECT * FROM sqlite_temp_master) "
|
|
"WHERE type='view' ORDER BY name")
|
|
rs = connection.execute(s)
|
|
except exc.DBAPIError:
|
|
s = ("SELECT name FROM sqlite_master "
|
|
"WHERE type='view' ORDER BY name")
|
|
rs = connection.execute(s)
|
|
|
|
return [row[0] for row in rs]
|
|
|
|
@reflection.cache
|
|
def get_view_definition(self, connection, view_name, schema=None, **kw):
|
|
quote = self.identifier_preparer.quote_identifier
|
|
if schema is not None:
|
|
qschema = self.identifier_preparer.quote_identifier(schema)
|
|
master = '%s.sqlite_master' % qschema
|
|
s = ("SELECT sql FROM %s WHERE name = '%s'"
|
|
"AND type='view'") % (master, view_name)
|
|
rs = connection.execute(s)
|
|
else:
|
|
try:
|
|
s = ("SELECT sql FROM "
|
|
" (SELECT * FROM sqlite_master UNION ALL "
|
|
" SELECT * FROM sqlite_temp_master) "
|
|
"WHERE name = '%s' "
|
|
"AND type='view'") % view_name
|
|
rs = connection.execute(s)
|
|
except exc.DBAPIError:
|
|
s = ("SELECT sql FROM sqlite_master WHERE name = '%s' "
|
|
"AND type='view'") % view_name
|
|
rs = connection.execute(s)
|
|
|
|
result = rs.fetchall()
|
|
if result:
|
|
return result[0].sql
|
|
|
|
@reflection.cache
|
|
def get_columns(self, connection, table_name, schema=None, **kw):
|
|
quote = self.identifier_preparer.quote_identifier
|
|
if schema is not None:
|
|
pragma = "PRAGMA %s." % quote(schema)
|
|
else:
|
|
pragma = "PRAGMA "
|
|
qtable = quote(table_name)
|
|
statement = "%stable_info(%s)" % (pragma, qtable)
|
|
c = _pragma_cursor(connection.execute(statement))
|
|
|
|
rows = c.fetchall()
|
|
columns = []
|
|
for row in rows:
|
|
(name, type_, nullable, default, primary_key) = \
|
|
(row[1], row[2].upper(), not row[3],
|
|
row[4], row[5])
|
|
|
|
columns.append(self._get_column_info(name, type_, nullable,
|
|
default, primary_key))
|
|
return columns
|
|
|
|
def _get_column_info(self, name, type_, nullable,
|
|
default, primary_key):
|
|
|
|
match = re.match(r'(\w+)(\(.*?\))?', type_)
|
|
if match:
|
|
coltype = match.group(1)
|
|
args = match.group(2)
|
|
else:
|
|
coltype = "VARCHAR"
|
|
args = ''
|
|
try:
|
|
coltype = self.ischema_names[coltype]
|
|
if args is not None:
|
|
args = re.findall(r'(\d+)', args)
|
|
coltype = coltype(*[int(a) for a in args])
|
|
except KeyError:
|
|
util.warn("Did not recognize type '%s' of column '%s'" %
|
|
(coltype, name))
|
|
coltype = sqltypes.NullType()
|
|
|
|
if default is not None:
|
|
default = unicode(default)
|
|
|
|
return {
|
|
'name': name,
|
|
'type': coltype,
|
|
'nullable': nullable,
|
|
'default': default,
|
|
'autoincrement': default is None,
|
|
'primary_key': primary_key
|
|
}
|
|
|
|
@reflection.cache
|
|
def get_pk_constraint(self, connection, table_name, schema=None, **kw):
|
|
cols = self.get_columns(connection, table_name, schema, **kw)
|
|
pkeys = []
|
|
for col in cols:
|
|
if col['primary_key']:
|
|
pkeys.append(col['name'])
|
|
return {'constrained_columns': pkeys, 'name': None}
|
|
|
|
@reflection.cache
|
|
def get_foreign_keys(self, connection, table_name, schema=None, **kw):
|
|
quote = self.identifier_preparer.quote_identifier
|
|
if schema is not None:
|
|
pragma = "PRAGMA %s." % quote(schema)
|
|
else:
|
|
pragma = "PRAGMA "
|
|
qtable = quote(table_name)
|
|
statement = "%sforeign_key_list(%s)" % (pragma, qtable)
|
|
c = _pragma_cursor(connection.execute(statement))
|
|
fkeys = []
|
|
fks = {}
|
|
while True:
|
|
row = c.fetchone()
|
|
if row is None:
|
|
break
|
|
(numerical_id, rtbl, lcol, rcol) = (row[0], row[2], row[3], row[4])
|
|
|
|
self._parse_fk(fks, fkeys, numerical_id, rtbl, lcol, rcol)
|
|
return fkeys
|
|
|
|
def _parse_fk(self, fks, fkeys, numerical_id, rtbl, lcol, rcol):
|
|
# sqlite won't return rcol if the table
|
|
# was created with REFERENCES <tablename>, no col
|
|
if rcol is None:
|
|
rcol = lcol
|
|
|
|
if self._broken_fk_pragma_quotes:
|
|
rtbl = re.sub(r'^[\"\[`\']|[\"\]`\']$', '', rtbl)
|
|
|
|
try:
|
|
fk = fks[numerical_id]
|
|
except KeyError:
|
|
fk = {
|
|
'name': None,
|
|
'constrained_columns': [],
|
|
'referred_schema': None,
|
|
'referred_table': rtbl,
|
|
'referred_columns': []
|
|
}
|
|
fkeys.append(fk)
|
|
fks[numerical_id] = fk
|
|
|
|
if lcol not in fk['constrained_columns']:
|
|
fk['constrained_columns'].append(lcol)
|
|
if rcol not in fk['referred_columns']:
|
|
fk['referred_columns'].append(rcol)
|
|
return fk
|
|
|
|
@reflection.cache
|
|
def get_indexes(self, connection, table_name, schema=None, **kw):
|
|
quote = self.identifier_preparer.quote_identifier
|
|
if schema is not None:
|
|
pragma = "PRAGMA %s." % quote(schema)
|
|
else:
|
|
pragma = "PRAGMA "
|
|
include_auto_indexes = kw.pop('include_auto_indexes', False)
|
|
qtable = quote(table_name)
|
|
statement = "%sindex_list(%s)" % (pragma, qtable)
|
|
c = _pragma_cursor(connection.execute(statement))
|
|
indexes = []
|
|
while True:
|
|
row = c.fetchone()
|
|
if row is None:
|
|
break
|
|
# ignore implicit primary key index.
|
|
# http://www.mail-archive.com/sqlite-users@sqlite.org/msg30517.html
|
|
elif (not include_auto_indexes and
|
|
row[1].startswith('sqlite_autoindex')):
|
|
continue
|
|
|
|
indexes.append(dict(name=row[1], column_names=[], unique=row[2]))
|
|
# loop thru unique indexes to get the column names.
|
|
for idx in indexes:
|
|
statement = "%sindex_info(%s)" % (pragma, quote(idx['name']))
|
|
c = connection.execute(statement)
|
|
cols = idx['column_names']
|
|
while True:
|
|
row = c.fetchone()
|
|
if row is None:
|
|
break
|
|
cols.append(row[2])
|
|
return indexes
|
|
|
|
|
|
def _pragma_cursor(cursor):
|
|
"""work around SQLite issue whereby cursor.description
|
|
is blank when PRAGMA returns no rows."""
|
|
|
|
if cursor.closed:
|
|
cursor.fetchone = lambda: None
|
|
cursor.fetchall = lambda: []
|
|
return cursor
|