"""MySQLdb Cursors
This module implements Cursors of various types for MySQLdb. By
default, MySQLdb uses the Cursor class.
"""
__revision__ = "$ Revision: $"[11:-2]
import re
INSERT_VALUES = re.compile(
r"^(P<start>.+\svalues\s*)(P<values>\(((?<!\\)'.*?\).*(?<!\\)?'|.)+?\))(P<end>.*)$",
re.IGNORECASE)
class BaseCursor(object):
"""A base for Cursor classes. Useful attributes:
description
A tuple of DB API 7-tuples describing the columns in
the last executed query; see PEP-249 for details.
description_flags
Tuple of column flags for last query, one entry per column
in the result set. Values correspond to those in
MySQLdb.constants.FLAG. See MySQL documentation (C API)
for more information. Non-standard extension.
arraysize
default number of rows fetchmany() will fetch
"""
from _mysql_exceptions import MySQLError, Warning, Error, InterfaceError, \
DatabaseError, DataError, OperationalError, IntegrityError, \
InternalError, ProgrammingError, NotSupportedError
_defer_warnings = False
_fetch_type = None
def __init__(self, connection):
from weakref import proxy
self.connection = proxy(connection)
self.description = None
self.description_flags = None
self.rowcount = -1
self.arraysize = 1
self._executed = None
self.lastrowid = None
self.messages = []
self.errorhandler = connection.errorhandler
self._result = None
self._warnings = 0
self._info = None
self.rownumber = None
def __del__(self):
self.close()
self.errorhandler = None
self._result = None
def close(self):
"""Close the cursor. No further queries will be possible."""
if not self.connection:
return
while self.nextset():
pass
self.connection = None
def _check_executed(self):
"""Ensure that .execute() has been called."""
if not self._executed:
self.errorhandler(self, self.ProgrammingError, "execute() first")
def _warning_check(self):
"""Check for warnings, and report via the warnings module."""
from warnings import warn
if self._warnings:
warnings = self._get_db().show_warnings()
if warnings:
# This is done in two loops in case
# Warnings are set to raise exceptions.
for warning in warnings:
self.messages.append((self.Warning, warning))
for warning in warnings:
warn(warning[-1], self.Warning, 3)
elif self._info:
self.messages.append((self.Warning, self._info))
warn(self._info, self.Warning, 3)
def nextset(self):
"""Advance to the next result set.
Returns None if there are no more result sets.
"""
if self._executed:
self.fetchall()
del self.messages[:]
connection = self._get_db()
num_rows = connection.next_result()
if num_rows == -1:
return None
self._do_get_result()
self._post_get_result()
self._warning_check()
return True
def _post_get_result(self):
"""Stub to be overridden by MixIn."""
def _get_result(self):
"""Stub to be overridden by MixIn."""
return []
def _do_get_result(self):
"""Get the result from the last query."""
connection = self._get_db()
self._result = self._get_result()
self.rowcount = connection.affected_rows()
self.rownumber = 0
self.description = self._result and self._result.describe() or None
self.description_flags = self._result and self._result.field_flags() or None
self.lastrowid = connection.insert_id()
self._warnings = connection.warning_count()
self._info = connection.info()
def setinputsizes(self, *args):
"""Does nothing, required by DB API."""
def setoutputsizes(self, *args):
"""Does nothing, required by DB API."""
def _get_db(self):
"""Get the database connection.
Raises ProgrammingError if the connection has been closed."""
if not self.connection:
self.errorhandler(self, self.ProgrammingError, "cursor closed")
return self.connection
def execute(self, query, args=None):
"""Execute a query.
query -- string, query to execute on server
args -- optional sequence or mapping, parameters to use with query.
Note: If args is a sequence, then %s must be used as the
parameter placeholder in the query. If a mapping is used,
%(key)s must be used as the placeholder.
Returns long integer rows affected, if any
"""
from sys import exc_info
del self.messages[:]
connection = self._get_db()
charset = connection.character_set_name()
if isinstance(query, unicode):
query = query.encode(charset)
if args is not None:
query = query % connection.literal(args)
try:
result = self._query(query)
except TypeError, msg:
if msg.args[0] in ("not enough arguments for format string",
"not all arguments converted"):
self.messages.append((self.ProgrammingError, msg.args[0]))
self.errorhandler(self, self.ProgrammingError, msg.args[0])
else:
self.messages.append((TypeError, msg))
self.errorhandler(self, TypeError, msg)
except:
exc, value, traceback = exc_info()
del traceback
self.messages.append((exc, value))
self.errorhandler(self, exc, value)
self._executed = query
if not self._defer_warnings:
self._warning_check()
return result
def executemany(self, query, args):
"""Execute a multi-row query.
query
string, query to execute on server
args
Sequence of sequences or mappings, parameters to use with
query.
Returns long integer rows affected, if any.
This method improves performance on multiple-row INSERT and
REPLACE. Otherwise it is equivalent to looping over args with
execute().
"""
del self.messages[:]
connection = self._get_db()
if not args:
return
charset = connection.character_set_name()
if isinstance(query, unicode):
query = query.encode(charset)
matched = INSERT_VALUES.match(query)
if not matched:
self.rowcount = sum([ self.execute(query, arg) for arg in args ])
return self.rowcount
start = matched.group('start')
end = matched.group('end')
values = matched.group('values')
try:
sql_params = [ values % connection.literal(arg) for arg in args ]
except TypeError, msg:
if msg.args[0] in ("not enough arguments for format string",
"not all arguments converted"):
self.messages.append((self.ProgrammingError, msg.args[0]))
self.errorhandler(self, self.ProgrammingError, msg.args[0])
else:
self.messages.append((TypeError, msg))
self.errorhandler(self, TypeError, msg)
except:
from sys import exc_info
exc, value, traceback = exc_info()
del traceback
self.errorhandler(self, exc, value)
self.rowcount = int(self._query(
'\n'.join([start, ',\n'.join(sql_params), end,
])))
if not self._defer_warnings:
self._warning_check()
return self.rowcount
def callproc(self, procname, args=()):
"""Execute stored procedure procname with args
procname
string, name of procedure to execute on server
args
Sequence of parameters to use with procedure
Returns the original args.
Compatibility warning: PEP-249 specifies that any modified
parameters must be returned. This is currently impossible
as they are only available by storing them in a server
variable and then retrieved by a query. Since stored
procedures return zero or more result sets, there is no
reliable way to get at OUT or INOUT parameters via callproc.
The server variables are named @_procname_n, where procname
is the parameter above and n is the position of the parameter
(from zero). Once all result sets generated by the procedure
have been fetched, you can issue a SELECT @_procname_0, ...
query using .execute() to get any OUT or INOUT values.
Compatibility warning: The act of calling a stored procedure
itself creates an empty result set. This appears after any
result sets generated by the procedure. This is non-standard
behavior with respect to the DB-API. Be sure to use nextset()
to advance through all result sets; otherwise you may get
disconnected.
"""
connection = self._get_db()
charset = connection.character_set_name()
for index, arg in enumerate(args):
query = "SET @_%s_%d=%s" % (procname, index,
connection.literal(arg))
if isinstance(query, unicode):
query = query.encode(charset)
self._query(query)
self.nextset()
query = "CALL %s(%s)" % (procname,
','.join(['@_%s_%d' % (procname, i)
for i in range(len(args))]))
if isinstance(query, unicode):
query = query.encode(charset)
self._query(query)
self._executed = query
if not self._defer_warnings:
self._warning_check()
return args
def _do_query(self, query):
"""Low-levey query wrapper. Overridden by MixIns."""
connection = self._get_db()
self._last_executed = query
connection.query(query)
self._do_get_result()
return self.rowcount
def _query(self, query):
"""Hook for _do_query."""
return self._do_query(query)
def _fetch_row(self, size=1):
"""Low-level fetch_row wrapper."""
if not self._result:
return ()
return self._result.fetch_row(size, self._fetch_type)
def __iter__(self):
return iter(self.fetchone, None)
def fetchone(self):
"""Stub to be overridden by a MixIn."""
return None
def fetchall(self):
"""Stub to be overridden by a MixIn."""
return []
class CursorStoreResultMixIn(object):
"""This is a MixIn class which causes the entire result set to be
stored on the client side, i.e. it uses mysql_store_result(). If the
result set can be very large, consider adding a LIMIT clause to your
query, or using CursorUseResultMixIn instead."""
def _get_result(self):
"""Low-level; uses mysql_store_result()"""
return self._get_db().store_result()
def _query(self, query):
"""Low-level; executes query, gets result, and returns rowcount."""
rowcount = self._do_query(query)
self._post_get_result()
return rowcount
def _post_get_result(self):
"""Low-level"""
self._rows = self._fetch_row(0)
self._result = None
def fetchone(self):
"""Fetches a single row from the cursor. None indicates that
no more rows are available."""
self._check_executed()
if self.rownumber >= len(self._rows):
return None
result = self._rows[self.rownumber]
self.rownumber += 1
return result
def fetchmany(self, size=None):
"""Fetch up to size rows from the cursor. Result set may be smaller
than size. If size is not defined, cursor.arraysize is used."""
self._check_executed()
end = self.rownumber + (size or self.arraysize)
result = self._rows[self.rownumber:end]
self.rownumber = min(end, len(self._rows))
return result
def fetchall(self):
"""Fetchs all available rows from the cursor."""
self._check_executed()
if self.rownumber:
result = self._rows[self.rownumber:]
else:
result = self._rows
self.rownumber = len(self._rows)
return result
def scroll(self, value, mode='relative'):
"""Scroll the cursor in the result set to a new position according
to mode.
If mode is 'relative' (default), value is taken as offset to
the current position in the result set, if set to 'absolute',
value states an absolute target position."""
self._check_executed()
if mode == 'relative':
row = self.rownumber + value
elif mode == 'absolute':
row = value
else:
self.errorhandler(self, self.ProgrammingError,
"unknown scroll mode %s" % `mode`)
if row < 0 or row >= len(self._rows):
self.errorhandler(self, IndexError, "out of range")
self.rownumber = row
def __iter__(self):
self._check_executed()
result = self.rownumber and self._rows[self.rownumber:] or self._rows
return iter(result)
class CursorUseResultMixIn(object):
"""This is a MixIn class which causes the result set to be stored
in the server and sent row-by-row to client side, i.e. it uses
mysql_use_result(). You MUST retrieve the entire result set and
close() the cursor before additional queries can be peformed on
the connection."""
_defer_warnings = True
def _get_result(self):
"""Low-level; calls mysql_use_result()"""
return self._get_db().use_result()
def fetchone(self):
"""Fetches a single row from the cursor."""
self._check_executed()
rows = self._fetch_row(1)
if not rows:
self._warning_check()
return None
self.rownumber = self.rownumber + 1
return rows[0]
def fetchmany(self, size=None):
"""Fetch up to size rows from the cursor. Result set may be smaller
than size. If size is not defined, cursor.arraysize is used."""
self._check_executed()
rows = self._fetch_row(size or self.arraysize)
self.rownumber = self.rownumber + len(rows)
if not rows:
self._warning_check()
return rows
def fetchall(self):
"""Fetchs all available rows from the cursor."""
self._check_executed()
rows = self._fetch_row(0)
self.rownumber = self.rownumber + len(rows)
self._warning_check()
return rows
def __iter__(self):
return self
def next(self):
row = self.fetchone()
if row is None:
raise StopIteration
return row
class CursorTupleRowsMixIn(object):
"""This is a MixIn class that causes all rows to be returned as tuples,
which is the standard form required by DB API."""
_fetch_type = 0
class CursorDictRowsMixIn(object):
"""This is a MixIn class that causes all rows to be returned as
dictionaries. This is a non-standard feature."""
_fetch_type = 1
class Cursor(CursorStoreResultMixIn, CursorTupleRowsMixIn,
BaseCursor):
"""This is the standard Cursor class that returns rows as tuples
and stores the result set in the client."""
class DictCursor(CursorStoreResultMixIn, CursorDictRowsMixIn,
BaseCursor):
"""This is a Cursor class that returns rows as dictionaries and
stores the result set in the client."""
class SSCursor(CursorUseResultMixIn, CursorTupleRowsMixIn,
BaseCursor):
"""This is a Cursor class that returns rows as tuples and stores
the result set in the server."""
class SSDictCursor(CursorUseResultMixIn, CursorDictRowsMixIn,
BaseCursor):
"""This is a Cursor class that returns rows as dictionaries and
stores the result set in the server."""
