flask扩展模块flask-sqlachemy 的使用
该篇博客配置环境为:python版本3.5，flask2.0，python3中已经不再支持MySQLdb模块，所有这里我用了pymysql，所有使用前应该安装pymysql:pip install pymysql
在网上的好多资料都给的是使用sqlite的例子，由于很不喜欢所以今天分享一下flask-sqlalchemy操作mysql的方法.
以前习惯使用sqlalchemy,后来发现使用flask-sqlchemy还是要简单一些（起码省去了好多模块和类的导入，create_engine,sessionmaker,declarative。。。）不过flask官方的例子用的是sqlchemy，去官网, flask-sqlalchemy官方文档
这里写一个简单的flask web程序，来说明flask-sqlalchemy如何驱动msyql数据库.为了偷懒，这个例子以上一篇博文flask蓝图的使用为基础.
首先看一下程序结构:
相比上一节只多了两个文件，create_db.py,models.py
1.建立mysql和app的连接
在config.py中加入以下两项配置:
SQLALCHEMY_DATABASE_URI = 'mysql+pymysql://root:xxxxx@localhost:3306/test?' SQLALCHEMY_TRACK_MODIFICATIONS = True
app.config.from_object(
db = SQLAlchemy(app)
就可以完成app和数据的关联，并生成一个可以操作app数据库的SQLAlchemy实例db 完整的app/__init__.py代码如下:
from flask import Flask, url_for, request, redirect, render_template
from flask_sqlalchemy import SQLAlchemy
app
= Flask(__name__)
app.config.from_object(
'config')
db
= SQLAlchemy(app)
from app import models,views
2.创建app/models.py模块
上代码
from app import db #db是在app/__init__.py生成的关联后的SQLAlchemy实例
class User(db.Model):__tablename__ = 'users' id
= db.Column(db.Integer, primary_key=True) username
= db.Column(db.String(80), unique=True) email
= db.Column(db.String(320), unique=True) password
= db.Column(db.String(32), nullable=False)
def __repr__(self):return '<User %r>' % self.username
class Admin(db.Model):__tablename__ = 'admins' id
= db.Column(db.Integer, primary_key=True) username
= db.Column(db.String(80), unique=True) email
= db.Column(db.String(320), unique=True) password
= db.Column(db.String(32), nullable=False)
def __repr__(self):return '<User %r>' % self.username
3.创建create_db.py，表结构设计完成后执行python create_db.py即可完成表的创建,如下图
#app/create_db.py
from app import db
db.create_all()
4.表已经创建完成了，接下来是我们的业务逻辑使用表的时候了
分别在user和admin蓝图中增加一个add用户的业务
#app/user.py
from flask import Blueprint, render_template, redirect,request
from app import db
from .models import User
user
= Blueprint('user',__name__)
@user.route(
'/index')
def index():return render_template('user/index.html')
@user.route(
'/add/',methods=['GET','POST'])
def add():if request.method == 'POST': p_user
= request.form.get('username',None) p_email
= request.form.get('email',None) p_password
= request.form.get('password',None)
if not p_user or not p_email or not p_password:return 'input error'
newobj
= User(username=p_user, email=p_email, password=p_password) db.session.add(newobj)
db.session.commit()
users
= User.query.all()return render_template('user/add.html',users=users) users
= User.query.all()return render_template('user/add.html',users=users)
@user.route(
'/show')
def show():return 'user_show'
#app/admin.py
#admin.py
from flask import Blueprint,render_template, request, redirect
from app import db
from .models import Admin
admin = Blueprint('admin',__name__)
@admin.route('/index')
def index():
return render_template('admin/index.html')
@admin.route('/add/',methods=['POST','GET'])
def add():
if request.method == 'POST':
p_admin = request.form.get('username',None)
p_email = request.form.get('email',None)
p_password = request.form.get('password',None)
if not p_admin or not p_email or not p_password:
return 'input error'
newobj = Admin(username=p_admin, email=p_email, password=p_password)
db.session.add(newobj)
db.session.commit()
admins = Admin.query.all()
return render_template('admin/add.html',admins=admins)
admins = Admin.query.all()
return render_template('admin/add.html',admins=admins)
@admin.route('/show')
def show():
return 'admin_show'
#app/templates/admin/add.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>AdminsAdd</title>
</head>
<body>
<form action="/admin/add/" method="POST">
user:<input type="text" name="username" />
email:<input type="text" name="email" />
pwd:<input type="password" name="password" />
<input type="submit" value="add" />
</form>
{% if admins %}
<table border="1px">
<tr>
<th>UserName</th>
<th>Email</th>
</tr>
{% for u in admins %}
<tr>
<td>{{u.username}}</td>
<td>{{u.email}}</td>
</tr>
{% endfor %}
</table>
{% endif %}
</body>
</html>
#app/templates/user/add.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>UserAdd</title>
</head>
<body>
<form action="/user/add/" method="POST">
user:<input type="text" name="username" />
email:<input type="text" name="email" />
pwd:<input type="password" name="password" />
<input type="submit" value="add" />
</form>
{% if users %}
<table border="1px">
<tr>
<th>UserName</th>
<th>Email</th>
</tr>
{% for u in users %}
<tr>
<td>{{u.username}}</td>
<td>{{u.email}}</td>
</tr>
{% endfor %}
</table>
{% endif %}
</body>
</html>
#app/views.py
from app import app
from .admin import admin
from .user import user
app.register_blueprint(admin,url_prefix='/admin')
app.register_blueprint(user, url_prefix='/user')
#run.py
from app import app
app.run()
到这里也就结束了，这样这个例子就结合了蓝图和flask-sqlalchemy.本例中只使用了db.session.add(),其它的还有db.session.delete()...
看一下效果:
localhost:5000/user/add
localhost:5000/admin/add
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