实例介绍
【实例简介】
【实例截图】
【实例截图】
【核心代码】
"""MySQLdb Cursors
This module implements Cursors of various types for MySQLdb. By
default, MySQLdb uses the Cursor class.
"""
import re
import sys
try:
from types import ListType, TupleType, UnicodeType
except ImportError:
# Python 3
ListType = list
TupleType = tuple
UnicodeType = str
restr = r"""
\s
values
\s*
(
\(
[^()']*
(?:
(?:
(?:\(
# ( - editor hightlighting helper
.*
\))
|
'
[^\\']*
(?:\\.[^\\']*)*
'
)
[^()']*
)*
\)
)
"""
insert_values = re.compile(restr, re.S | re.I | re.X)
from _mysql_exceptions import Warning, Error, InterfaceError, DataError, \
DatabaseError, OperationalError, IntegrityError, InternalError, \
NotSupportedError, ProgrammingError
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
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):
if not self._executed:
self.errorhandler(self, ProgrammingError, "execute() first")
def _warning_check(self):
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 w in warnings:
self.messages.append((self.Warning, w))
for w in warnings:
warn(w[-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[:]
db = self._get_db()
nr = db.next_result()
if nr == -1:
return None
self._do_get_result()
self._post_get_result()
self._warning_check()
return 1
def _post_get_result(self): pass
def _do_get_result(self):
db = self._get_db()
self._result = self._get_result()
self.rowcount = db.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 = db.insert_id()
self._warnings = db.warning_count()
self._info = db.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):
if not self.connection:
self.errorhandler(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
"""
del self.messages[:]
db = self._get_db()
if isinstance(query, unicode):
query = query.encode(db.unicode_literal.charset)
if args is not None:
if isinstance(args, dict):
query = query % dict((key, db.literal(item))
for key, item in args.iteritems())
else:
query = query % tuple([db.literal(item) for item in args])
try:
r = None
r = self._query(query)
except TypeError, m:
if m.args[0] in ("not enough arguments for format string",
"not all arguments converted"):
self.messages.append((ProgrammingError, m.args[0]))
self.errorhandler(self, ProgrammingError, m.args[0])
else:
self.messages.append((TypeError, m))
self.errorhandler(self, TypeError, m)
except (SystemExit, KeyboardInterrupt):
raise
except:
exc, value, tb = sys.exc_info()
del tb
self.messages.append((exc, value))
self.errorhandler(self, exc, value)
self._executed = query
if not self._defer_warnings: self._warning_check()
return r
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[:]
db = self._get_db()
if not args: return
if isinstance(query, unicode):
query = query.encode(db.unicode_literal.charset)
m = insert_values.search(query)
if not m:
r = 0
for a in args:
r = r self.execute(query, a)
return r
p = m.start(1)
e = m.end(1)
qv = m.group(1)
try:
q = []
for a in args:
if isinstance(a, dict):
q.append(qv % dict((key, db.literal(item))
for key, item in a.iteritems()))
else:
q.append(qv % tuple([db.literal(item) for item in a]))
except TypeError, msg:
if msg.args[0] in ("not enough arguments for format string",
"not all arguments converted"):
self.errorhandler(self, ProgrammingError, msg.args[0])
else:
self.errorhandler(self, TypeError, msg)
except (SystemExit, KeyboardInterrupt):
raise
except:
exc, value, tb = sys.exc_info()
del tb
self.errorhandler(self, exc, value)
r = self._query('\n'.join([query[:p], ',\n'.join(q), query[e:]]))
if not self._defer_warnings: self._warning_check()
return r
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()
for index, arg in enumerate(args):
q = "SET @_%s_%d=%s" % (procname, index,
db.literal(arg))
if isinstance(q, unicode):
q = q.encode(db.unicode_literal.charset)
self._query(q)
self.nextset()
q = "CALL %s(%s)" % (procname,
','.join(['@_%s_%d' % (procname, i)
for i in range(len(args))]))
if type(q) is UnicodeType:
q = q.encode(db.unicode_literal.charset)
self._query(q)
self._executed = q
if not self._defer_warnings: self._warning_check()
return args
def _do_query(self, q):
db = self._get_db()
self._last_executed = q
db.query(q)
self._do_get_result()
return self.rowcount
def _query(self, q): return self._do_query(q)
def _fetch_row(self, size=1):
if not self._result:
return ()
return self._result.fetch_row(size, self._fetch_type)
def __iter__(self):
return iter(self.fetchone, None)
Warning = Warning
Error = Error
InterfaceError = InterfaceError
DatabaseError = DatabaseError
DataError = DataError
OperationalError = OperationalError
IntegrityError = IntegrityError
InternalError = InternalError
ProgrammingError = ProgrammingError
NotSupportedError = NotSupportedError
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): return self._get_db().store_result()
def _query(self, q):
rowcount = self._do_query(q)
self._post_get_result()
return rowcount
def _post_get_result(self):
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 = 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':
r = self.rownumber value
elif mode == 'absolute':
r = value
else:
self.errorhandler(self, ProgrammingError,
"unknown scroll mode %s" % repr(mode))
if r < 0 or r >= len(self._rows):
self.errorhandler(self, 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 peformed on
the connection."""
_defer_warnings = True
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:
self._warning_check()
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)
if not r:
self._warning_check()
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)
self._warning_check()
return r
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
def fetchoneDict(self):
"""Fetch a single row as a dictionary. Deprecated:
Use fetchone() instead. Will be removed in 1.3."""
from warnings import warn
warn("fetchoneDict() is non-standard and will be removed in 1.3",
DeprecationWarning, 2)
return self.fetchone()
def fetchmanyDict(self, size=None):
"""Fetch several rows as a list of dictionaries. Deprecated:
Use fetchmany() instead. Will be removed in 1.3."""
from warnings import warn
warn("fetchmanyDict() is non-standard and will be removed in 1.3",
DeprecationWarning, 2)
return self.fetchmany(size)
def fetchallDict(self):
"""Fetch all available rows as a list of dictionaries. Deprecated:
Use fetchall() instead. Will be removed in 1.3."""
from warnings import warn
warn("fetchallDict() is non-standard and will be removed in 1.3",
DeprecationWarning, 2)
return self.fetchall()
class CursorOldDictRowsMixIn(CursorDictRowsMixIn):
"""This is a MixIn class that returns rows as dictionaries with
the same key convention as the old Mysqldb (MySQLmodule). Don't
use this."""
_fetch_type = 2
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."""
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