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417 lines
13 KiB
Python
417 lines
13 KiB
Python
"""MySQLdb Cursors
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This module implements Cursors of various types for MySQLdb. By
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default, MySQLdb uses the Cursor class.
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"""
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import re
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insert_values = re.compile(r'\svalues\s*(\(.+\))', re.IGNORECASE)
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from _mysql_exceptions import Warning, Error, InterfaceError, DataError, \
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DatabaseError, OperationalError, IntegrityError, InternalError, \
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NotSupportedError, ProgrammingError
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import exceptions
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if hasattr(exceptions, "StopIteration"):
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_EndOfData = exceptions.StopIteration
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else:
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_EndOfData = exceptions.IndexError
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class BaseCursor:
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"""A base for Cursor classes. Useful attributes:
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description -- DB API 7-tuple describing columns in last query
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arraysize -- default number of rows fetchmany() will fetch
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See the MySQL docs for more information."""
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from _mysql_exceptions import MySQLError, Warning, Error, InterfaceError, \
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DatabaseError, DataError, OperationalError, IntegrityError, \
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InternalError, ProgrammingError, NotSupportedError
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def __init__(self, connection):
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self.connection = connection
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self.description = None
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self.rowcount = -1
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self.arraysize = 100
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self._executed = None
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self.lastrowid = None
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self.messages = []
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self.errorhandler = connection.errorhandler
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def __del__(self):
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self.close()
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def close(self):
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"""Close the cursor. No further queries will be possible."""
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self.connection = None
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self.errorhandler = None
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def _check_executed(self):
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if not self._executed:
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self.errorhandler(self.connection, self,
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ProgrammingError, "execute() first")
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def setinputsizes(self, *args):
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"""Does nothing, required by DB API."""
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def setoutputsizes(self, *args):
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"""Does nothing, required by DB API."""
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def _get_db(self):
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if not self.connection:
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self.errorhandler(self.connection, self,
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ProgrammingError, "cursor closed")
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return self.connection._db
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def execute(self, query, args=None):
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"""Execute a query.
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query -- string, query to execute on server
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args -- optional sequence or mapping, parameters to use with query.
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returns long integer rows affected, if any"""
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from types import ListType, TupleType
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if args is None:
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r = self._query(query)
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elif type(args) is ListType and type(args[0]) is TupleType:
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r = self.executemany(query, args) # deprecated
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else:
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try:
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r = self._query(query % self.connection.literal(args))
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except TypeError, m:
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if m.args[0] in ("not enough arguments for format string",
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"not all arguments converted"):
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self.errorhandler(self.connection, self,
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ProgrammingError, m.args[0])
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else:
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raise
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self._executed = query
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return r
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def executemany(self, query, args):
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"""Execute a multi-row query.
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query -- string, query to execute on server
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args -- sequence of sequences or mappings, parameters to use with
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query. The query must contain the clause "values ( ... )".
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The parenthetical portion will be repeated once for each
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item in the sequence.
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returns long integer rows affected, if any
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This method performs multiple-row inserts and similar queries."""
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from string import join
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m = insert_values.search(query)
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if not m: raise ProgrammingError, "can't find values"
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p = m.start(1)
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qv = query[p:]
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qargs = self.connection.literal(args)
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try:
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q = [ query % qargs[0] ]
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for a in qargs[1:]: q.append( qv % a )
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except TypeError, msg:
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if msg.args[0] in ("not enough arguments for format string",
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"not all arguments converted"):
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self.errorhandler(self.connection, self,
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ProgrammingError, msg.args[0])
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else:
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raise
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r = self._query(join(q,',\n'))
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self._executed = query
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return r
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def __do_query(self, q):
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from string import split, atoi
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db = self._get_db()
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db.query(q)
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self._result = self._get_result()
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self.rowcount = db.affected_rows()
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self.rownumber = 0
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self.description = self._result and self._result.describe() or None
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self.lastrowid = db.insert_id()
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message = db.info()
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if message: self.messages.append(message)
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self._check_for_warnings()
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return self.rowcount
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def _check_for_warnings(self): pass
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_query = __do_query
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def info(self):
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"""Return some information about the last query (db.info())
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DEPRECATED: Use messages attribute"""
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self._check_executed()
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if self.messages:
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return self.messages[0]
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else:
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return ''
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def insert_id(self):
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"""Return the last inserted ID on an AUTO_INCREMENT columns.
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DEPRECATED: use lastrowid attribute"""
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self._check_executed()
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return self.lastrowid
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def _fetch_row(self, size=1):
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return self._result.fetch_row(size, self._fetch_type)
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def next(self):
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"""Fetches the next row. If using Python 2.1 or newer,
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StopIteration is raised when there are no more rows.
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Otherwise, IndexError is raised."""
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result = self.fetchone()
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if result is None:
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raise _EndOfData
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return result
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def __iter__(self): return self # XXX
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Warning = Warning
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Error = Error
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InterfaceError = InterfaceError
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DatabaseError = DatabaseError
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DataError = DataError
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OperationalError = OperationalError
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IntegrityError = IntegrityError
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InternalError = InternalError
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ProgrammingError = ProgrammingError
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NotSupportedError = NotSupportedError
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class CursorWarningMixIn:
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"""This is a MixIn class that provides the capability of raising
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the Warning exception when something went slightly wrong with your
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query."""
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def _check_for_warnings(self):
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from string import atoi, split
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if self.messages:
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warnings = atoi(split(self.messages[0])[-1])
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if warnings:
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raise Warning, self.messages[0]
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class CursorStoreResultMixIn:
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"""This is a MixIn class which causes the entire result set to be
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stored on the client side, i.e. it uses mysql_store_result(). If the
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result set can be very large, consider adding a LIMIT clause to your
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query, or using CursorUseResultMixIn instead."""
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def _get_result(self): return self._get_db().store_result()
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def close(self):
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"""Close the cursor. Further queries will not be possible."""
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self._rows = ()
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BaseCursor.close(self)
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def _query(self, q):
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rowcount = self._BaseCursor__do_query(q)
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self._rows = self._result and self._fetch_row(0) or ()
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del self._result
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return rowcount
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def fetchone(self):
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"""Fetches a single row from the cursor."""
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self._check_executed()
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if self.rownumber >= len(self._rows): return None
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result = self._rows[self.rownumber]
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self.rownumber = self.rownumber+1
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return result
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def fetchmany(self, size=None):
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"""Fetch up to size rows from the cursor. Result set may be smaller
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than size. If size is not defined, cursor.arraysize is used."""
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self._check_executed()
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end = self.rownumber + (size or self.arraysize)
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result = self._rows[self.rownumber:end]
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self.rownumber = min(end, len(self._rows))
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return result
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def fetchall(self):
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"""Fetchs all available rows from the cursor."""
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self._check_executed()
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result = self.rownumber and self._rows[self.rownumber:] or self._rows
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self.rownumber = len(self._rows)
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return result
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def seek(self, row, whence=0):
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"""seek to a given row of the result set analogously to file.seek().
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This is non-standard extension. DEPRECATED: Use scroll method"""
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self._check_executed()
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if whence == 0:
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self.rownumber = row
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elif whence == 1:
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self.rownumber = self.rownumber + row
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elif whence == 2:
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self.rownumber = len(self._rows) + row
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def tell(self):
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"""Return the current position in the result set analogously to
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file.tell(). This is a non-standard extension. DEPRECATED:
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use rownumber attribute"""
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self._check_executed()
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return self.rownumber
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def scroll(self, value, mode='relative'):
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"""Scroll the cursor in the result set to a new position according
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to mode.
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If mode is 'relative' (default), value is taken as offset to
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the current position in the result set, if set to 'absolute',
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value states an absolute target position."""
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self._check_executed()
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if mode == 'relative':
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r = self.rownumber + value
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elif mode == 'absolute':
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r = value
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else:
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raise ProgrammingError, "unknown scroll mode %s" % `mode`
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if r < 0 or r >= len(self._rows):
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raise IndexError, "out of range"
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self.rownumber = r
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class CursorUseResultMixIn:
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"""This is a MixIn class which causes the result set to be stored
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in the server and sent row-by-row to client side, i.e. it uses
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mysql_use_result(). You MUST retrieve the entire result set and
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close() the cursor before additional queries can be peformed on
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the connection."""
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def close(self):
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"""Close the cursor. No further queries can be executed."""
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self._result = None
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BaseCursor.close(self)
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def _get_result(self): return self._get_db().use_result()
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def fetchone(self):
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"""Fetches a single row from the cursor."""
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self._check_executed()
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r = self._fetch_row(1)
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if not r: return None
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self.rownumber = self.rownumber + 1
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return r[0]
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def fetchmany(self, size=None):
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"""Fetch up to size rows from the cursor. Result set may be smaller
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than size. If size is not defined, cursor.arraysize is used."""
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self._check_executed()
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r = self._fetch_row(size or self.arraysize)
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self.rownumber = self.rownumber + len(r)
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return r
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def fetchall(self):
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"""Fetchs all available rows from the cursor."""
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self._check_executed()
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r = self._fetch_row(0)
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self.rownumber = self.rownumber + len(r)
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return r
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class CursorTupleRowsMixIn:
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"""This is a MixIn class that causes all rows to be returned as tuples,
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which is the standard form required by DB API."""
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_fetch_type = 0
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class CursorDictRowsMixIn:
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"""This is a MixIn class that causes all rows to be returned as
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dictionaries. This is a non-standard feature."""
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_fetch_type = 1
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def fetchoneDict(self):
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"""Fetch a single row as a dictionary. Deprecated:
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Use fetchone() instead."""
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return self.fetchone()
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def fetchmanyDict(self, size=None):
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"""Fetch several rows as a list of dictionaries. Deprecated:
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Use fetchmany() instead."""
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return self.fetchmany(size)
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def fetchallDict(self):
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"""Fetch all available rows as a list of dictionaries. Deprecated:
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Use fetchall() instead."""
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return self.fetchall()
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class CursorOldDictRowsMixIn(CursorDictRowsMixIn):
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"""This is a MixIn class that returns rows as dictionaries with
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the same key convention as the old Mysqldb (MySQLmodule). Don't
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use this."""
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_fetch_type = 2
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class CursorNW(CursorStoreResultMixIn, CursorTupleRowsMixIn,
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BaseCursor):
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"""This is a basic Cursor class that returns rows as tuples and
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stores the result set in the client. Warnings are not raised."""
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class Cursor(CursorWarningMixIn, CursorNW):
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"""This is the standard Cursor class that returns rows as tuples
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and stores the result set in the client. Warnings are raised as
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necessary."""
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class DictCursorNW(CursorStoreResultMixIn, CursorDictRowsMixIn,
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BaseCursor):
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"""This is a Cursor class that returns rows as dictionaries and
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stores the result set in the client. Warnings are not raised."""
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class DictCursor(CursorWarningMixIn, DictCursorNW):
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"""This is a Cursor class that returns rows as dictionaries and
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stores the result set in the client. Warnings are raised as
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necessary."""
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class SSCursorNW(CursorUseResultMixIn, CursorTupleRowsMixIn,
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BaseCursor):
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"""This is a basic Cursor class that returns rows as tuples and
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stores the result set in the server. Warnings are not raised."""
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class SSCursor(CursorWarningMixIn, SSCursorNW):
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"""This is a Cursor class that returns rows as tuples and stores
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the result set in the server. Warnings are raised as necessary."""
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class SSDictCursorNW(CursorUseResultMixIn, CursorDictRowsMixIn,
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BaseCursor):
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"""This is a Cursor class that returns rows as dictionaries and
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stores the result set in the server. Warnings are not raised."""
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class SSDictCursor(CursorWarningMixIn, SSDictCursorNW):
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"""This is a Cursor class that returns rows as dictionaries and
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stores the result set in the server. Warnings are raised as
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necessary."""
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