491 lines
16 KiB
Python
491 lines
16 KiB
Python
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"""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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from __future__ import print_function, absolute_import
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from functools import partial
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import re
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import sys
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from .compat import unicode
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from ._exceptions import (
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Warning, Error, InterfaceError, DataError,
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DatabaseError, OperationalError, IntegrityError, InternalError,
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NotSupportedError, ProgrammingError)
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#: Regular expression for :meth:`Cursor.executemany`.
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#: executemany only supports simple bulk insert.
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#: You can use it to load large dataset.
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RE_INSERT_VALUES = re.compile(
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r"\s*((?:INSERT|REPLACE)\b.+\bVALUES?\s*)" +
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r"(\(\s*(?:%s|%\(.+\)s)\s*(?:,\s*(?:%s|%\(.+\)s)\s*)*\))" +
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r"(\s*(?:ON DUPLICATE.*)?);?\s*\Z",
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re.IGNORECASE | re.DOTALL)
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class BaseCursor(object):
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"""A base for Cursor classes. Useful attributes:
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description
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A tuple of DB API 7-tuples describing the columns in
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the last executed query; see PEP-249 for details.
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description_flags
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Tuple of column flags for last query, one entry per column
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in the result set. Values correspond to those in
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MySQLdb.constants.FLAG. See MySQL documentation (C API)
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for more information. Non-standard extension.
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arraysize
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default number of rows fetchmany() will fetch
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"""
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#: Max stetement size which :meth:`executemany` generates.
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#:
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#: Max size of allowed statement is max_allowed_packet - packet_header_size.
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#: Default value of max_allowed_packet is 1048576.
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max_stmt_length = 64*1024
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from ._exceptions import (
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MySQLError, Warning, Error, InterfaceError,
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DatabaseError, DataError, OperationalError, IntegrityError,
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InternalError, ProgrammingError, NotSupportedError,
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)
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connection = None
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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.description_flags = None
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self.rowcount = -1
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self.arraysize = 1
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self._executed = None
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# XXX THIS IS GARBAGE: While this is totally garbage and private,
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# Django 1.11 depends on it. And they don't fix it because
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# they are in security-only fix mode.
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# So keep this garbage for now. This will be removed in 1.5.
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# See PyMySQL/mysqlclient-python#303
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self._last_executed = None
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self.lastrowid = None
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self.messages = []
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self._result = None
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self._warnings = None
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self.rownumber = None
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self._rows = None
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def close(self):
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"""Close the cursor. No further queries will be possible."""
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try:
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if self.connection is None:
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return
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while self.nextset():
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pass
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finally:
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self.connection = None
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self._result = None
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def __enter__(self):
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return self
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def __exit__(self, *exc_info):
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del exc_info
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self.close()
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def _escape_args(self, args, conn):
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encoding = conn.encoding
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literal = conn.literal
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def ensure_bytes(x):
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if isinstance(x, unicode):
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return x.encode(encoding)
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elif isinstance(x, tuple):
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return tuple(map(ensure_bytes, x))
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elif isinstance(x, list):
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return list(map(ensure_bytes, x))
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return x
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if isinstance(args, (tuple, list)):
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ret = tuple(literal(ensure_bytes(arg)) for arg in args)
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elif isinstance(args, dict):
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ret = {ensure_bytes(key): literal(ensure_bytes(val))
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for (key, val) in args.items()}
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else:
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# If it's not a dictionary let's try escaping it anyways.
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# Worst case it will throw a Value error
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ret = literal(ensure_bytes(args))
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ensure_bytes = None # break circular reference
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return ret
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def _check_executed(self):
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if not self._executed:
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raise ProgrammingError("execute() first")
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def nextset(self):
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"""Advance to the next result set.
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Returns None if there are no more result sets.
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"""
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if self._executed:
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self.fetchall()
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del self.messages[:]
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db = self._get_db()
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nr = db.next_result()
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if nr == -1:
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return None
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self._do_get_result(db)
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self._post_get_result()
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return 1
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def _do_get_result(self, db):
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self._result = result = self._get_result()
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if result is None:
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self.description = self.description_flags = None
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else:
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self.description = result.describe()
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self.description_flags = result.field_flags()
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self.rowcount = db.affected_rows()
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self.rownumber = 0
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self.lastrowid = db.insert_id()
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self._warnings = None
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def _post_get_result(self):
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pass
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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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con = self.connection
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if con is None:
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raise ProgrammingError("cursor closed")
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return con
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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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Note: If args is a sequence, then %s must be used as the
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parameter placeholder in the query. If a mapping is used,
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%(key)s must be used as the placeholder.
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Returns integer represents rows affected, if any
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"""
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while self.nextset():
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pass
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db = self._get_db()
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if isinstance(query, unicode):
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query = query.encode(db.encoding)
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if args is not None:
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if isinstance(args, dict):
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nargs = {}
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for key, item in args.items():
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if isinstance(key, unicode):
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key = key.encode(db.encoding)
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nargs[key] = db.literal(item)
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args = nargs
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else:
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args = tuple(map(db.literal, args))
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try:
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query = query % args
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except TypeError as m:
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raise ProgrammingError(str(m))
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assert isinstance(query, (bytes, bytearray))
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res = self._query(query)
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return res
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def executemany(self, query, args):
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# type: (str, list) -> int
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"""Execute a multi-row query.
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:param query: query to execute on server
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:param args: Sequence of sequences or mappings. It is used as parameter.
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:return: Number of rows affected, if any.
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This method improves performance on multiple-row INSERT and
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REPLACE. Otherwise it is equivalent to looping over args with
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execute().
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"""
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del self.messages[:]
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if not args:
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return
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m = RE_INSERT_VALUES.match(query)
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if m:
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q_prefix = m.group(1) % ()
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q_values = m.group(2).rstrip()
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q_postfix = m.group(3) or ''
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assert q_values[0] == '(' and q_values[-1] == ')'
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return self._do_execute_many(q_prefix, q_values, q_postfix, args,
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self.max_stmt_length,
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self._get_db().encoding)
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self.rowcount = sum(self.execute(query, arg) for arg in args)
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return self.rowcount
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def _do_execute_many(self, prefix, values, postfix, args, max_stmt_length, encoding):
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conn = self._get_db()
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escape = self._escape_args
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if isinstance(prefix, unicode):
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prefix = prefix.encode(encoding)
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if isinstance(values, unicode):
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values = values.encode(encoding)
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if isinstance(postfix, unicode):
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postfix = postfix.encode(encoding)
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sql = bytearray(prefix)
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args = iter(args)
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v = values % escape(next(args), conn)
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sql += v
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rows = 0
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for arg in args:
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v = values % escape(arg, conn)
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if len(sql) + len(v) + len(postfix) + 1 > max_stmt_length:
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rows += self.execute(sql + postfix)
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sql = bytearray(prefix)
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else:
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sql += b','
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sql += v
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rows += self.execute(sql + postfix)
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self.rowcount = rows
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return rows
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def callproc(self, procname, args=()):
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"""Execute stored procedure procname with args
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procname -- string, name of procedure to execute on server
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args -- Sequence of parameters to use with procedure
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Returns the original args.
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Compatibility warning: PEP-249 specifies that any modified
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parameters must be returned. This is currently impossible
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as they are only available by storing them in a server
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variable and then retrieved by a query. Since stored
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procedures return zero or more result sets, there is no
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reliable way to get at OUT or INOUT parameters via callproc.
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The server variables are named @_procname_n, where procname
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is the parameter above and n is the position of the parameter
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(from zero). Once all result sets generated by the procedure
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have been fetched, you can issue a SELECT @_procname_0, ...
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query using .execute() to get any OUT or INOUT values.
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Compatibility warning: The act of calling a stored procedure
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itself creates an empty result set. This appears after any
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result sets generated by the procedure. This is non-standard
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behavior with respect to the DB-API. Be sure to use nextset()
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to advance through all result sets; otherwise you may get
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disconnected.
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"""
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db = self._get_db()
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if isinstance(procname, unicode):
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procname = procname.encode(db.encoding)
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if args:
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fmt = b'@_' + procname + b'_%d=%s'
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q = b'SET %s' % b','.join(fmt % (index, db.literal(arg))
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for index, arg in enumerate(args))
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self._query(q)
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self.nextset()
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q = b"CALL %s(%s)" % (procname,
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b','.join([b'@_%s_%d' % (procname, i)
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for i in range(len(args))]))
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self._query(q)
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return args
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def _query(self, q):
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db = self._get_db()
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self._result = None
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db.query(q)
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self._do_get_result(db)
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self._post_get_result()
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self._executed = q
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self._last_executed = q # XXX THIS IS GARBAGE: See above.
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return self.rowcount
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def _fetch_row(self, size=1):
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if not self._result:
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return ()
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return self._result.fetch_row(size, self._fetch_type)
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def __iter__(self):
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return iter(self.fetchone, None)
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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 CursorStoreResultMixIn(object):
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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):
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return self._get_db().store_result()
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def _post_get_result(self):
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self._rows = self._fetch_row(0)
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self._result = None
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def fetchone(self):
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"""Fetches a single row from the cursor. None indicates that
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no more rows are available."""
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self._check_executed()
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if self.rownumber >= len(self._rows):
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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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if self.rownumber:
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result = self._rows[self.rownumber:]
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else:
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result = self._rows
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self.rownumber = len(self._rows)
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return result
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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()
|
||
|
|
if mode == 'relative':
|
||
|
|
r = self.rownumber + value
|
||
|
|
elif mode == 'absolute':
|
||
|
|
r = value
|
||
|
|
else:
|
||
|
|
raise ProgrammingError("unknown scroll mode %s" % repr(mode))
|
||
|
|
if r < 0 or r >= len(self._rows):
|
||
|
|
raise IndexError("out of range")
|
||
|
|
self.rownumber = r
|
||
|
|
|
||
|
|
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 performed on
|
||
|
|
the connection."""
|
||
|
|
|
||
|
|
def _get_result(self):
|
||
|
|
return self._get_db().use_result()
|
||
|
|
|
||
|
|
def fetchone(self):
|
||
|
|
"""Fetches a single row from the cursor."""
|
||
|
|
self._check_executed()
|
||
|
|
r = self._fetch_row(1)
|
||
|
|
if not r:
|
||
|
|
return None
|
||
|
|
self.rownumber = self.rownumber + 1
|
||
|
|
return r[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()
|
||
|
|
r = self._fetch_row(size or self.arraysize)
|
||
|
|
self.rownumber = self.rownumber + len(r)
|
||
|
|
return r
|
||
|
|
|
||
|
|
def fetchall(self):
|
||
|
|
"""Fetchs all available rows from the cursor."""
|
||
|
|
self._check_executed()
|
||
|
|
r = self._fetch_row(0)
|
||
|
|
self.rownumber = self.rownumber + len(r)
|
||
|
|
return r
|
||
|
|
|
||
|
|
def __iter__(self):
|
||
|
|
return self
|
||
|
|
|
||
|
|
def next(self):
|
||
|
|
row = self.fetchone()
|
||
|
|
if row is None:
|
||
|
|
raise StopIteration
|
||
|
|
return row
|
||
|
|
|
||
|
|
__next__ = next
|
||
|
|
|
||
|
|
|
||
|
|
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."""
|