# 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