利用redis协助mysql数据库搬迁_mysql教程_开发教程

　最近公司新项目上线，需要数据库搬迁，但新版本和老版本数据库差距比较大，关系也比较复杂。如果用传统办法，需要撰写很多mysql脚本，工程量虽然不大，但对于没有dba的公司来说，稍微有点难度。本人就勉为其难，用redis作为mysql中转站，先把原来的mysql数据转移到redis里面，再从redis转换到新的mysql。整个过程脉络清晰，脚本简单。

　　首先，公司之前的项目是，flask+sqlalchemy的方式，直接复制原来的model文件，稍微修改一下，就有以下代码。

# coding:utf-8

from sqlalchemy import create_engine, ForeignKey, Column, Integer, String, Text, DateTime, Boolean, and_, or_,\

SmallInteger, func, Numeric, select, Float, Table, TIMESTAMP, DECIMAL, desc

from sqlalchemy.orm import relationship, backref, sessionmaker, scoped_session

from sqlalchemy.ext.declarative import declarative_base

from sqlalchemy.ext.hybrid import hybrid_property, hybrid_method, Comparator

from sqlalchemy import event

import redis

import json

mysql_info = "mysql://username:password@ip_address:3306/databasename?charset=utf8"

redis_store = redis.Redis(host='127.0.0.1', port=6380, password='password', db=5)

engine = create_engine(mysql_info, pool_recycle=7200)

Base = declarative_base()

class User(Base):

__tablename__ = 'user'

id = Column('id', Integer, primary_key=True)

phone_number = Column('phone_number', String(11), index=True)

password = Column('password', String(30))

nickname = Column('nickname', String(30), index=True, nullable=True)

headpic = Column('headpic', String(100), nullable=True)

register_time = Column('register_time', DateTime, index=True)

email = Column('email', String(50), default='', index=True)

real_name = Column('real_name', String(50), default='', index=True)

user_admin = Column('user_admin', Integer, index=True, default=0)

rc_token = Column('rc_token', String(100))

device_token = Column('device_token', String(100), unique=True, nullable=True)

unit_id = Column('unit_id', Integer, ForeignKey('unit.id'))

unit = relationship("Unit", backref=backref('users'))

def to_dict(self):

return dict(id=self.id, phone_number=self.phone_number,

password=self.password, nickname=self.nickname,

headpic=self.headpic, register_time=self.register_time.strftime('%Y-%m-%d %H:%M:%S'),

user_admin=self.user_admin, rc_token=self.rc_token,

unit_id=self.unit_id, device_token=self.device_token,

)

class Group(Base):

__tablename__ = 'groups'

id = Column('id', Integer, primary_key=True)

name = Column('name', String(100), index=True)

address = Column('address', String(100), index=True, nullable=True)

contact_person = Column('contactperson', String(30), nullable=True)

contact_number = Column('contactnumber', String(30), nullable=True)

unit_id = Column('unit_id', Integer, ForeignKey('unit.id'))

unit = relationship('Unit', backref=backref('groups'))

class Monitor(Base):

__tablename__ = 'monitor'

id = Column('id', Integer, primary_key=True)

u_id = Column('sn_num', String(10), index=True)

phone_num = Column('phone_num', String(20), index=True, nullable=True)

name = Column('name', String(40), index=True, nullable=True)

position = Column('position', String(40), nullable=True)

join_time = Column('join_time', DateTime, index=True, nullable=True)

group_id = Column('group_id', Integer, ForeignKey('groups.id'))

group = relationship("Group", backref=backref('monitors'))

longitude = Column('longitude', DECIMAL(12, 9), default=31.000000)

latitude = Column('latitude', DECIMAL(12, 9), default=121.000000)

def to_dict(self):

unit_id = self.group.unit_id

return dict(id=self.id, u_id=self.u_id, phone_num=self.phone_num, name=self.name,

position=self.position, join_time=self.join_time.strftime('%Y-%m-%d %H:%M:%S'), unit_id=unit_id,

longitude=str(self.longitude), latitude=str(self.latitude))

class Unit(Base):

__tablename__ = 'unit'

id = Column('id', Integer, primary_key=True)

name = Column('name', String(100), index=True, nullable=True)

address = Column('address', String(100), index=True, nullable=True)

contact_person = Column('contactperson', String(30), index=True, nullable=True)

contact_number = Column('contactnumber', String(30), nullable=True)

device_operation_password = Column('device_operation_password', String(4), nullable=True)

rc_group_id = Column('rc_group_id', String(50), index=True, nullable=True)

rc_group_name = Column('rc_group_name', String(50), index=True, nullable=True)

longitude = Column('longitude', DECIMAL(12, 9), nullable=True)

latitude = Column('latitude', DECIMAL(12, 9), nullable=True)

active = Column('active', SmallInteger, index=True, default=0)

def to_dict(self):

return dict(id=self.id, name=self.name, address=self.address,

contact_person=self.contact_person, contact_number=self.contact_number,

device_operation_password=self.device_operation_password,

rc_group_id=self.rc_group_id, rc_group_name=self.rc_group_name,

longitude=str(self.longitude), latitude=str(self.latitude), active=self.active)

db_session = scoped_session(sessionmaker(autocommit=False,

autoflush=False,

bind=engine))

Base.query = db_session.query_property()

def old_sql_2_redis():

redis_store.flushdb()

units = Unit.query.all()

[redis_store.rpush('units', json.dumps(unit.to_dict())) for unit in units]

users = User.query.all()

[redis_store.rpush('users', json.dumps(user.to_dict())) for user in users]

monitors = Monitor.query.all()

[redis_store.rpush('monitors', json.dumps(monitor.to_dict())) for monitor in monitors]

if __name__ == '__main__':

old_sql_2_redis()

把原来的数据库复制到本地redis了，看查看里面的元素。比如user数据，直接建一个user的list，每个appened其json格式的数据就可以了。主要注意点就是，如果新版本的表中没有的字段，就不要写入的redis了。

第二步就是把本地redis里面的数据，放到新的数据库上。这边要注意以下，把需要修改的地方要标示出来，可能加了其他字段，这些字段没有默认值的话，要自己添加上。过程也比较简单。

# coding:utf-8

from sqlalchemy import create_engine, ForeignKey, Column, Integer, String, Text, DateTime, Boolean, and_, or_,\

SmallInteger, func, Numeric, select, Float, Table, TIMESTAMP, DECIMAL, desc

from sqlalchemy.orm import relationship, backref, sessionmaker, scoped_session

from sqlalchemy.ext.declarative import declarative_base

from sqlalchemy.ext.hybrid import hybrid_property, hybrid_method, Comparator

from sqlalchemy import event

import redis

import json

import datetime

import uuid

mysql_info = "mysql://username:password@ip_address:3306/database_name?charset=utf8"

redis_store = redis.Redis(host='127.0.0.1', port=6380, password='password', db=5)

engine = create_engine(mysql_info, pool_recycle=7200)

Base = declarative_base()

class User(Base):

__tablename__ = 'user'

id = Column('id', Integer, primary_key=True)

phone_number = Column('phone_number', String(11), index=True)

password = Column('password', String(30))

nickname = Column('nickname', String(30), index=True, nullable=True)

headpic = Column('headpic', String(100), nullable=True)

register_time = Column('register_time', DateTime, index=True, default=datetime.datetime.now)

user_admin = Column('user_admin', SmallInteger, index=True, default=0)

hidden_user = Column('hidden_user', SmallInteger, index=True, default=0)

rc_token = Column('rc_token', String(100), nullable=True)

device_token = Column('device_token', String(100), unique=True, nullable=True)

unit_id = Column('unit_id', Integer, ForeignKey('unit.id'))

unit = relationship('Unit', backref=backref('users'))

class Monitor(Base):

__tablename__ = 'monitor'

id = Column('id', Integer, primary_key=True)

# device_type 1代表灭弧 2代表电气火灾

device_type = Column('device_type', SmallInteger, index=True, default=1)

u_id = Column('sn_num', String(10), index=True)

phone_num = Column('phone_num', String(20), index=True, nullable=True)

name = Column('name', String(40), index=True)

position = Column('position', String(40), nullable=True)

join_time = Column('join_time', DateTime, index=True)

longitude = Column('longitude', DECIMAL(12, 9), default=31.000000)

latitude = Column('latitude', DECIMAL(12, 9), default=121.000000)

unit_id = Column('unit_id', Integer, ForeignKey('unit.id'))

class Unit(Base):

__tablename__ = 'unit'

id = Column('id', Integer, primary_key=True)

name = Column('name', String(100), index=True)

address = Column('address', String(100), index=True, nullable=True)

contact_person = Column('contactperson', String(30), nullable=True)

contact_number = Column('contactnumber', String(30), nullable=True)

device_operation_password = Column('device_operation_password', String(4), default='1234')

rc_group_id = Column('rc_group_id', String(36), default=str(uuid.uuid1()))

rc_group_name = Column('rc_group_name', String(50), nullable=True)

longitude = Column('longitude', DECIMAL(12, 9), default=31.000000)

latitude = Column('latitude', DECIMAL(12, 9), default=121.000000)

active = Column('active', SmallInteger, index=True, default=0)

is_group = Column('is_group', SmallInteger, index=True, default=0)

parent_id = Column('parent_id', Integer, ForeignKey('unit.id'))

db_session = scoped_session(sessionmaker(autocommit=False,

autoflush=False,

bind=engine))

Base.query = db_session.query_property()

def redis_2_new_sql():

units_json = redis_store.lrange('units', 0, -1)

units = [Unit(is_group=0, parent_id=None, **json.loads(unit_json)) for unit_json in units_json]

[db_session.add(unit) for unit in units]

try:

db_session.commit()

except Exception as e:

print e

db_session.rollback()

return

users_json = redis_store.lrange('users', 0, -1)

users = [User(hidden_user=0, **json.loads(uer_json)) for uer_json in users_json]

[db_session.add(user) for user in users]

try:

db_session.commit()

except Exception as e:

print e

db_session.rollback()

return

monitors_json = redis_store.lrange('monitors', 0, -1)

monitors = [Monitor(**json.loads(monitor_json)) for monitor_json in monitors_json]

[db_session.add(monitor) for monitor in monitors]

try:

db_session.commit()

except Exception as e:

print e

db_session.rollback()

return

if __name__ == '__main__':

redis_2_new_sql()

整个过程相当简单，需要注意的就是，前后顺序，因为user和monitor都有一个外键指向unit，所以要先恢复unit表，这样就不会出错了。

看来以后我有新方法搬迁数据库了。

(责任编辑：好模板)