python - 如何使用mysqldb进行本地mysql连接

Question

错误是

File "c:\python27\lib\site-packages\MySQLdb\connections.py", line 72, in Connection
db = get_db_connection(db_name)
NameError: name 'get_db_connection' is not defined

所以我认为错误在 * 这是因为 def init(self, *args, **kwargs): 以冒号结尾但我不不知道连接的语法。

这是我在 connection.py 中的类连接代码

class Connection(_mysql.connection):

"""MySQL Database Connection Object"""

default_cursor = cursors.Cursor

def __init__(self, *args, **kwargs):     # *** this is error I think ie the : but what is syntax

    def get_db_connection(database_name):
        db = MySQLdb.connect('localhost', 'user', 'pswrd', database_name)
        cur = db.cursor()
    return db, cur

db_name = 'test' # database name
user_name = 'root' # name of a user

db = get_db_connection(db_name)


"""

Create a connection to the database. It is strongly recommended
that you only use keyword parameters. Consult the MySQL C API
documentation for more information.

host
  string, host to connect

user
  string, user to connect as

passwd
  string, password to use

db
  string, database to use

port
  integer, TCP/IP port to connect to

unix_socket
  string, location of unix_socket to use

conv
  conversion dictionary, see MySQLdb.converters

connect_timeout
  number of seconds to wait before the connection attempt
  fails.

compress
  if set, compression is enabled

named_pipe
  if set, a named pipe is used to connect (Windows only)

init_command
  command which is run once the connection is created

read_default_file
  file from which default client values are read

read_default_group
  configuration group to use from the default file

cursorclass
  class object, used to create cursors (keyword only)

use_unicode
  If True, text-like columns are returned as unicode objects
  using the connection's character set.  Otherwise, text-like
  columns are returned as strings.  columns are returned as
  normal strings. Unicode objects will always be encoded to
  the connection's character set regardless of this setting.

charset
  If supplied, the connection character set will be changed
  to this character set (MySQL-4.1 and newer). This implies
  use_unicode=True.

sql_mode
  If supplied, the session SQL mode will be changed to this
  setting (MySQL-4.1 and newer). For more details and legal
  values, see the MySQL documentation.

client_flag
  integer, flags to use or 0
  (see MySQL docs or constants/CLIENTS.py)

ssl
  dictionary or mapping, contains SSL connection parameters;
  see the MySQL documentation for more details
  (mysql_ssl_set()).  If this is set, and the client does not
  support SSL, NotSupportedError will be raised.

local_infile
  integer, non-zero enables LOAD LOCAL INFILE; zero disables

There are a number of undocumented, non-standard methods. See the
documentation for the MySQL C API for some hints on what they do.

"""

from MySQLdb.constants import CLIENT, FIELD_TYPE
from MySQLdb.converters import conversions
from weakref import proxy, WeakValueDictionary

import types

kwargs2 = kwargs.copy()

if 'conv' in kwargs:
    conv = kwargs['conv']
else:
    conv = conversions

conv2 = {}
for k, v in conv.items():
    if isinstance(k, int) and isinstance(v, list):
        conv2[k] = v[:]
    else:
        conv2[k] = v
kwargs2['conv'] = conv2

cursorclass = kwargs2.pop('cursorclass', self.default_cursor)
charset = kwargs2.pop('charset', '')

if charset:
    use_unicode = True
else:
    use_unicode = False

use_unicode = kwargs2.pop('use_unicode', use_unicode)
sql_mode = kwargs2.pop('sql_mode', '')

client_flag = kwargs.get('client_flag', 0)
client_version = tuple([ numeric_part(n) for n in _mysql.get_client_info().split('.')[:2] ])
if client_version >= (4, 1):
    client_flag |= CLIENT.MULTI_STATEMENTS
if client_version >= (5, 0):
    client_flag |= CLIENT.MULTI_RESULTS

kwargs2['client_flag'] = client_flag

super(Connection, self).__init__(*args, **kwargs2)     #****
self.cursorclass = cursorclass
self.encoders = dict([ (k, v) for k, v in conv.items()
                       if type(k) is not int ])

self._server_version = tuple([ numeric_part(n) for n in self.get_server_info().split('.')[:2] ])

db = proxy(self)
def _get_string_literal():
    def string_literal(obj, dummy=None):
        return db.string_literal(obj)
    return string_literal

def _get_unicode_literal():
    def unicode_literal(u, dummy=None):
        return db.literal(u.encode(unicode_literal.charset))
    return unicode_literal

def _get_string_decoder():
    def string_decoder(s):
        return s.decode(string_decoder.charset)
    return string_decoder

string_literal = _get_string_literal()
self.unicode_literal = unicode_literal = _get_unicode_literal()
self.string_decoder = string_decoder = _get_string_decoder()
if not charset:
    charset = self.character_set_name()
self.set_character_set(charset)

if sql_mode:
    self.set_sql_mode(sql_mode)

if use_unicode:
    self.converter[FIELD_TYPE.STRING].append((None, string_decoder))
    self.converter[FIELD_TYPE.VAR_STRING].append((None, string_decoder))
    self.converter[FIELD_TYPE.VARCHAR].append((None, string_decoder))
    self.converter[FIELD_TYPE.BLOB].append((None, string_decoder))

self.encoders[types.StringType] = string_literal
self.encoders[types.UnicodeType] = unicode_literal
self._transactional = self.server_capabilities & CLIENT.TRANSACTIONS
if self._transactional:
    # PEP-249 requires autocommit to be initially off
    self.autocommit(False)
self.messages = []

def cursor(self, cursorclass=None):
    """

    Create a cursor on which queries may be performed. The
    optional cursorclass parameter is used to create the
    Cursor. By default, self.cursorclass=cursors.Cursor is
    used.

    """
    return (cursorclass or self.cursorclass)(self)

def __enter__(self): return self.cursor()

def __exit__(self, exc, value, tb):
    if exc:
        self.rollback()
    else:
        self.commit()

def literal(self, o):
    """

    If o is a single object, returns an SQL literal as a string.
    If o is a non-string sequence, the items of the sequence are
    converted and returned as a sequence.

    Non-standard. For internal use; do not use this in your
    applications.

    """
    return self.escape(o, self.encoders)

def begin(self):
    """Explicitly begin a connection. Non-standard.
    DEPRECATED: Will be removed in 1.3.
    Use an SQL BEGIN statement instead."""
    from warnings import warn
    warn("begin() is non-standard and will be removed in 1.3",
         DeprecationWarning, 2)
    self.query("BEGIN")

if not hasattr(_mysql.connection, 'warning_count'):

    def warning_count(self):
        """Return the number of warnings generated from the
        last query. This is derived from the info() method."""
        from string import atoi
        info = self.info()
        if info:
            return atoi(info.split()[-1])
        else:
            return 0

def set_character_set(self, charset):
    """Set the connection character set to charset. The character
    set can only be changed in MySQL-4.1 and newer. If you try
    to change the character set from the current value in an
    older version, NotSupportedError will be raised."""
    if charset == "utf8mb4":
        py_charset = "utf8"
    else:
        py_charset = charset
    if self.character_set_name() != charset:
        try:
            super(Connection, self).set_character_set(charset)
        except AttributeError:
            if self._server_version < (4, 1):
                raise NotSupportedError("server is too old to set charset")
            self.query('SET NAMES %s' % charset)
            self.store_result()
    self.string_decoder.charset = py_charset
    self.unicode_literal.charset = py_charset

def set_sql_mode(self, sql_mode):
    """Set the connection sql_mode. See MySQL documentation for
    legal values."""
    if self._server_version < (4, 1):
        raise NotSupportedError("server is too old to set sql_mode")
    self.query("SET SESSION sql_mode='%s'" % sql_mode)
    self.store_result()

def show_warnings(self):
    """Return detailed information about warnings as a
    sequence of tuples of (Level, Code, Message). This
    is only supported in MySQL-4.1 and up. If your server
    is an earlier version, an empty sequence is returned."""
    if self._server_version < (4,1): return ()
    self.query("SHOW WARNINGS")
    r = self.store_result()
    warnings = r.fetch_row(0)
    return warnings

Warning = Warning
Error = Error
InterfaceError = InterfaceError
DatabaseError = DatabaseError
DataError = DataError
OperationalError = OperationalError
IntegrityError = IntegrityError
InternalError = InternalError
ProgrammingError = ProgrammingError
NotSupportedError = NotSupportedError

errorhandler = defaulterrorhandler

这是调用该函数的 connection.py 中的第 187 行

    super(Connection, self).__init__(*args, **kwargs2)     #****

Answer 1

来自 Connection.__init__ 文档字符串 - 强烈建议您仅使用关键字参数。

尝试使用类似的东西:

MySQLdb.connect(
    host='localhost',
    user='user',
    passwd='pswrd',
    db=database_name
)

此外，发布您遇到的错误。这可能会有所帮助。