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"""
MySQLdb Cursors
---------------
This module implements the Cursor class. You should not try to
create Cursors direction; use connection.cursor() instead.
"""
__revision__ = "$Revision$"[11:-2]
__author__ = "$Author$"[9:-2]
import re
import sys
import weakref
from MySQLdb.converters import get_codec, tuple_row_decoder
INSERT_VALUES = re.compile(r"(?P<start>.+values\s*)"
r"(?P<values>\(((?<!\\)'[^\)]*?\)[^\)]*(?<!\\)?'|[^\(\)]|(?:\([^\)]*\)))+\))"
r"(?P<end>.*)", re.I)
class Cursor(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.
arraysize
default number of rows fetchmany() will fetch
"""
from MySQLdb.exceptions import MySQLError, Warning, Error, InterfaceError, \
DatabaseError, DataError, OperationalError, IntegrityError, \
InternalError, ProgrammingError, NotSupportedError
_defer_warnings = False
_fetch_type = None
def __init__(self, connection, encoders, decoders):
self.connection = weakref.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
self.maxrows = 0
self.encoders = encoders
self.decoders = decoders
self._row_decoders = ()
self.row_decoder = tuple_row_decoder
def _flush(self):
"""_flush() reads to the end of the current result set, buffering what
it can, and then releases the result set."""
if self._result:
for row in self._result:
pass
self._result = None
def __del__(self):
self.close()
self.errorhandler = None
self._result = None
def _reset(self):
while True:
if self._result:
for row in self._result:
pass
self._result = None
if not self.nextset():
break
del self.messages[:]
def close(self):
"""Close the cursor. No further queries will be possible."""
if not self.connection:
return
self._flush()
try:
while self.nextset():
pass
except:
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
result = connection.use_result()
self._result = result
if result:
self.field_flags = result.field_flags()
self._row_decoders = [ get_codec(field, self.decoders) for field in result.fields ]
self.description = result.describe()
else:
self._row_decoders = self.field_flags = ()
self.description = None
self.rowcount = -1 #connection.affected_rows()
self.rownumber = 0
self.lastrowid = connection.insert_id()
self._warnings = connection.warning_count()
self._info = connection.info()
return True
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._db
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
"""
db = self._get_db()
self._reset()
charset = db.character_set_name()
if isinstance(query, unicode):
query = query.encode(charset)
try:
if args is not None:
query = query % tuple(map(self.connection.literal, args))
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 = sys.exc_info()
del traceback
self.messages.append((exc, value))
self.errorhandler(self, exc, value)
if not self._defer_warnings:
self._warning_check()
return None
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().
"""
db = self._get_db()
self._reset()
if not args:
return
charset = self.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')
values = matched.group('values')
end = matched.group('end')
try:
sql_params = ( values % tuple(map(self.connection.literal, row)) for row in args )
multirow_query = '\n'.join([start, ',\n'.join(sql_params), end])
self._query(multirow_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 = sys.exc_info()
del traceback
self.errorhandler(self, exc, value)
if not self._defer_warnings:
self._warning_check()
return None
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.
"""
db = self._get_db()
charset = self.connection.character_set_name()
for index, arg in enumerate(args):
query = "SET @_%s_%d=%s" % (procname, index,
self.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)
if not self._defer_warnings:
self._warning_check()
return args
def __iter__(self):
return iter(self.fetchone, None)
def _query(self, query):
"""Low-level; executes query, gets result, sets up decoders."""
connection = self._get_db()
self._flush()
self._executed = query
connection.query(query)
result = connection.use_result()
self._result = result
if result:
self.field_flags = result.field_flags()
self._row_decoders = [ get_codec(field, self.decoders) for field in result.fields ]
self.description = result.describe()
else:
self._row_decoders = self.field_flags = ()
self.description = None
self.rowcount = -1 #connection.affected_rows()
self.rownumber = 0
self.lastrowid = connection.insert_id()
self._warnings = connection.warning_count()
self._info = connection.info()
def fetchone(self):
"""Fetches a single row from the cursor. None indicates that
no more rows are available."""
self._check_executed()
row = self.row_decoder(self._row_decoders, self._result.simple_fetch_row())
return row
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()
if size is None:
size = self.arraysize
rows = []
for i in range(size):
row = self.row_decoder(self._row_decoders, self._result.simple_fetch_row())
if row is None: break
rows.append(row)
return rows
def fetchall(self):
"""Fetches all available rows from the cursor."""
self._check_executed()
if self._result:
rows = [ self.row_decoder(self._row_decoders, row) for row in self._result ]
else:
rows = []
return rows
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