一、数据库迁移
1、安装
pip install flask-script
pip install flask-migrate
2、创建迁移对象
代码语言：javascript复制<span class="hljs-keyword">from</span> flask_script <span class="hljs-keyword">import</span> Manager
<span class="hljs-keyword">from</span> flask_migrate <span class="hljs-keyword">import</span> Migrate, MigrateCommand
migrate = Migrate(app, db)
manager = Manager(app)
manager.add_command(<span class="hljs-string">"db"</span>, MigrateCommand)
<span class="hljs-keyword">if</span> __name__ == <span class="hljs-string">"__main__"</span>:
manager.run()
3、创建迁移文件目录
python manage.py db init
结果：在工程目录下自动生成一个名为migrations的目录
4、生成迁移文件
python manage.py db migrate -m “说明信息，注意不能有中文”
代码语言：javascript复制python manage.py db migrate -m <span class="hljs-string">"first"</span>
结果：在versions目录下生成迁移文件
5、执行迁移(更新数据库)
python manage.py db upgrade
6、查看迁移历史版本
python manage.py db history
二、普通方式数据增删改
注意
- sqlalchemy默认是开启了事务处理
- 每次操作完需要db.session.commit 或者 db.session.rollback()
1、添加数据
添加一条数据
代码语言：javascript复制<span class="hljs-meta">@view.route('/insert/')</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">insert</span><span class="hljs-params">()</span>:</span>
<span class="hljs-keyword">try</span>:
u = User(uusername=<span class="hljs-string">'lucky'</span>, usex=<span class="hljs-keyword">True</span>, uage=<span class="hljs-number">18</span>, uinfo=<span class="hljs-string">'lucky个人信息'</span>)
db.session.add(u)
db.session.commit()
<span class="hljs-keyword">except</span>:
db.session.rollback()
<span class="hljs-keyword">return</span> <span class="hljs-string">'添加一条数据'</span>
添加多条数据
代码语言：javascript复制<span class="hljs-meta">@view.route('/insert_many/')</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">insert_many</span><span class="hljs-params">()</span>:</span>
<span class="hljs-keyword">try</span>:
u1 = User(uusername=<span class="hljs-string">'lucky'</span>, usex=<span class="hljs-keyword">True</span>, uage=<span class="hljs-number">18</span>, uinfo=<span class="hljs-string">'lucky个人信息'</span>)
u1 = User(uusername=<span class="hljs-string">'迪丽热巴'</span>, usex=<span class="hljs-keyword">False</span>, uage=<span class="hljs-number">28</span>, uinfo=<span class="hljs-string">'迪丽热巴个人信息'</span>)
db.session.add_all([u1, u2])
db.session.commit()
<span class="hljs-keyword">except</span>:
db.session.rollback()
<span class="hljs-keyword">return</span> <span class="hljs-string">'添加多条数据'</span>
2、修改数据
代码语言：javascript复制<span class="hljs-meta">@view.route('/update/')</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">update</span><span class="hljs-params">()</span>:</span>
u = User.query.get(<span class="hljs-number">1</span>)
<span class="hljs-keyword">try</span>:
u.uusername = <span class="hljs-string">'杨幂'</span>
db.session.add(data)
db.session.commit()
<span class="hljs-keyword">except</span>:
db.session.rollback()
<span class="hljs-keyword">return</span> <span class="hljs-string">'修改'</span>
3、删除数据
代码语言：javascript复制<span class="hljs-meta">@view.route('/delete/')</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">delete</span><span class="hljs-params">()</span>:</span>
<span class="hljs-keyword">try</span>:
data = User.query.get(<span class="hljs-number">1</span>)
db.session.delete(data)
db.session.commit()
<span class="hljs-keyword">except</span>:
db.session.rollback()
<span class="hljs-keyword">return</span> <span class="hljs-string">'删除数据'</span>
三、定义增删改基础类与使用
1、定义类
db.py
代码语言：javascript复制<span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">DBParent</span><span class="hljs-params">()</span>:</span>
<span class="hljs-comment"># 添加和修改的方法</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">save</span><span class="hljs-params">(self)</span>:</span>
<span class="hljs-keyword">try</span>:
db.session.add(self) <span class="hljs-comment"># 添加对象到数据库 self代表当前类的实例化的对象</span>
db.session.commit()
<span class="hljs-keyword">return</span> <span class="hljs-keyword">True</span> <span class="hljs-comment">#成功 返回 True</span>
<span class="hljs-keyword">except</span>:
db.session.rollback()
<span class="hljs-keyword">return</span> <span class="hljs-keyword">False</span> <span class="hljs-comment"># 失败回滚返回False</span>
<span class="hljs-comment"># 添加所有的方法</span>
<span class="hljs-meta"> @staticmethod</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">saveAll</span><span class="hljs-params">(*args)</span>:</span>
<span class="hljs-keyword">try</span>:
db.session.add_all(*args)
db.session.commit()
<span class="hljs-keyword">return</span> <span class="hljs-keyword">True</span>
<span class="hljs-keyword">except</span>:
db.session.rollback()
<span class="hljs-keyword">return</span> <span class="hljs-keyword">False</span>
<span class="hljs-comment"># 删除的方法</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">delete</span><span class="hljs-params">(self)</span>:</span>
<span class="hljs-keyword">try</span>:
db.session.delete(self)
db.session.commit()
<span class="hljs-keyword">return</span> <span class="hljs-keyword">True</span>
<span class="hljs-keyword">except</span>:
db.session.rollback()
<span class="hljs-keyword">return</span> <span class="hljs-keyword">False</span>
db.DBParent = DBParent
模型继承DBParent
代码语言：javascript复制<span class="hljs-keyword">from</span> exts <span class="hljs-keyword">import</span> db
<span class="hljs-comment"># 继承db.DBParent，就拥有了自定义类的方法</span>
<span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">User</span><span class="hljs-params">(db.Model, db.DBParent)</span>:</span>
...
2、使用
添加数据
添加一条数据
代码语言：javascript复制<span class="hljs-meta">@view.route('/insert/')</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">insert</span><span class="hljs-params">()</span>:</span>
u = User(uusername=<span class="hljs-string">'lucky'</span>, usex=<span class="hljs-keyword">True</span>, uage=<span class="hljs-number">18</span>, uinfo=<span class="hljs-string">'lucky个人信息'</span>)
u.save()
<span class="hljs-keyword">return</span> <span class="hljs-string">'添加一条数据'</span>
添加多条数据
代码语言：javascript复制<span class="hljs-meta">@view.route('/insert_many/')</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">insert_many</span><span class="hljs-params">()</span>:</span>
u1 = User(uusername=<span class="hljs-string">'lucky'</span>, usex=<span class="hljs-keyword">True</span>, uage=<span class="hljs-number">18</span>, uinfo=<span class="hljs-string">'lucky个人信息'</span>)
u1 = User(uusername=<span class="hljs-string">'迪丽热巴'</span>, usex=<span class="hljs-keyword">False</span>, uage=<span class="hljs-number">28</span>, uinfo=<span class="hljs-string">'迪丽热巴个人信息'</span>)
User.saveAll(u1, u2)
<span class="hljs-keyword">return</span> <span class="hljs-string">'添加多条数据'</span>
修改数据
代码语言：javascript复制<span class="hljs-meta">@view.route('/update/')</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">update</span><span class="hljs-params">()</span>:</span>
u = User.query.get(<span class="hljs-number">1</span>)
u.uusername = <span class="hljs-string">'lucky'</span>
u.save()
<span class="hljs-keyword">return</span> <span class="hljs-string">'修改'</span>
删除数据
代码语言：javascript复制<span class="hljs-meta">@view.route('/delete/')</span>
<span class="hljs-function"><span class="hljs-keyword">def</span> <span class="hljs-title">delete</span><span class="hljs-params">()</span>:</span>
u = User.query.get(<span class="hljs-number">1</span>)
u.delete()
<span class="hljs-keyword">return</span> <span class="hljs-string">'删除'</span>
