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我想在运行12.04的Ubuntu机器上使用mysql创建远程数据库。InvalidRequestError:VARCHAR需要在方言上的长度mysql
它有一个启用了远程登录并且没有密码的root用户。我已经启动了服务器。输出的
sudo netstat -tap | grep mysql
显示
tcp 0 0 localhost:mysql *:* LISTEN 13246/mysqld
我已经创建了一个称为nwtopology使用数据库(如所提到的根不具有密码尚未。)
create database nwtopology
grant all privileges on *.* to [email protected]
FLUSH PRIVILEGES;
从同时运行Ubuntu 12.04的客户端机器我使用python脚本使用sqlal连接到远程mysql数据库chemy。
from pox.core import core
import pox.openflow.libopenflow_01 as of
import re
import datetime
import time
from sqlalchemy import create_engine, ForeignKey
from sqlalchemy import Column, Date, Integer, String
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship, backref
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.sql.expression import exists
log = core.getLogger()
engine = create_engine('mysql://[email protected]/nwtopology', echo=False)
Base = declarative_base()
Session = sessionmaker(bind=engine)
session = Session()
class SourcetoPort(Base):
""""""
__tablename__ = 'source_to_port'
id = Column(Integer, primary_key=True)
port_no = Column(Integer)
src_address = Column(String,index=True)
#-----------------------------------------
def __init__(self, src_address,port_no):
""""""
self.src_address = src_address
self.port_no = port_no
#create tables
Base.metadata.create_all(engine)
最后一行
Base.metadata.create_all(engine)
返回错误
File "/usr/lib/python2.7/dist-packages/sqlalchemy/sql/compiler.py", line 1699, in visit_string
return self.visit_VARCHAR(type_)
File "/usr/lib/python2.7/dist-packages/sqlalchemy/dialects/mysql/base.py", line 1654, in visit_VARCHAR
self.dialect.name)
InvalidRequestError: VARCHAR requires a length on dialect mysql
这是什么意思?我怎样才能在MySQL上设置VARCHAR长度?我对sqlalchemy和mysql非常陌生。