1：下载相关模块
pip install sqlalchemy
pip install sqlalchemy-migrate
2:创建model （model.py),这里用来绑定数据库，创建sqlmodel，当然你也可以吧数据库设置和model分开。
#coding:utf-8
#made by dewei
from sqlalchemy import *
from sqlalchemy.ext.declarative import declarative_base # db 基类
from sqlalchemy import Column, Integer, String, DateTime # 相应的列
from sqlalchemy.orm import sessionmaker, relationship, backref, scoped_session # 执行的相关方法
from sqlalchemy.dialects.mysql import LONGTEXT
import os
"""
设置数据库参数
"""
MYSQL_DB = 'sqlalchemy_migratetest'
MYSQL_USER = 'root'
MYSQL_PASSWD = 'dewei'
MYSQL_HOST = 'localhost'
MYSQL_POST = 3306
basedir = os.path.abspath(os.path.dirname(__file__))
SQLALCHEMY_DATABASE_URI = "mysql://%s:%s@%s:%s/%s?charset=utf8" % (MYSQL_USER, MYSQL_PASSWD, MYSQL_HOST, MYSQL_POST, MYSQL_DB)
SQLALCHEMY_MIGRATE_REPO = os.path.join(basedir, 'db_repository') # 设置数据库迁移保存的文件夹，用来sqlalchemymigrate
db = create_engine(SQLALCHEMY_DATABASE_URI, echo=True)
Base = declarative_base()
db_session = scoped_session(sessionmaker(autocommit=False,
autoflush=False,
bind=db))
Base.query = db_session.query_property()
def isenit_db():
Base.metadata.create_all(bind=db)
class User(Base):
__tablename__ = "user"
id = Column(Integer, primary_key=True)
username = Column(String(100), unique=True, nullable=False)
password = Column(String(200), nullable=False)
email = Column(String(200), nullable=False)
def __init__(self, username, password, email):
self.username = username
self.password = password
self.email = email
def repr(self):
return "" % (self.username, self.password)
3：生成 数据库并创建migrate迁移初始化 db_create.py
from model import SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO, db, Base
from migrate.versioning import api
import os.path
Base.metadata.create_all(bind=db)
if not os.path.exists(SQLALCHEMY_MIGRATE_REPO):
api.create(SQLALCHEMY_MIGRATE_REPO, 'database repository')
api.version_control(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
else:
api.version_control(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO, api.version(SQLALCHEMY_MIGRATE_REPO))
当完成本py后 执行一次 仅一次就好， python db_create.py 这样数据库就创建好了 并且migrate也初始化完成，然后创建第四部，以后 添加数据库 就使用他就可以了
4 创建同步数据库py db_migrate.py
import imp
from migrate.versioning import api
from model import Base
from model import SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO
migration = SQLALCHEMY_MIGRATE_REPO + '/versions/d_migration.py' % (api.db_version(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO) + 1)
tmp_module = imp.new_module('old_model')
old_model = api.create_model(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
exec old_model in tmp_module.__dict__
script = api.make_update_script_for_model(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO, tmp_module.meta, Base.metadata)
open(migration, 'wt').write(script)
api.upgrade(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
print 'New migration saved as ' + migration
print 'Current database version: ' + str(api.db_version(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO))
完成后 试着修改一次数据库 比如给user添加个新的字段 然后执行 python db_migrate.py 去sql里看看 已经添加完成了！