Flask-sqlalchemy---实战

逃离我推掉我的手 2022-10-06 08:00 172阅读 0赞

# 前言 #

flask+mysql

--------------------

# 安装sqlalchemy #

*  pip安装

pip install -U Flask-SQLAlchemy

*  源码安装：

python setup.py install

两种安装方式，我使用第一种安装方式：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyMzcwOTEz_size_16_color_FFFFFF_t_70]

*  安装依赖

pip install mysqlclient

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyMzcwOTEz_size_16_color_FFFFFF_t_70 1]

# 代码练习 #

app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://root:root@127.0.0.1/test_flask'

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyMzcwOTEz_size_16_color_FFFFFF_t_70 2]

*  绑定到Flask对象

db=SQLAlchemy(app)

通过此对象与数据库进行连接

在实际引用：

from flask_sqlalchemy import SQLAlchemy

报错，通过命令查看我已经成功安装了上面的库：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyMzcwOTEz_size_16_color_FFFFFF_t_70 3]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyMzcwOTEz_size_16_color_FFFFFF_t_70 4]  
我现在把之前安装的库卸载以后，重新安装试一试：

pip uninstall Flask-sqlalchemy

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyMzcwOTEz_size_16_color_FFFFFF_t_70 5]  
![在这里插入图片描述][20210612102016249.png]  
执行如下命令试一试：

pip install flask-sqlalchemy

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyMzcwOTEz_size_16_color_FFFFFF_t_70 6]  
执行上面的命令，不是大小写的问题，那开始修改编辑器引入此模块：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyMzcwOTEz_size_16_color_FFFFFF_t_70 7]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyMzcwOTEz_size_16_color_FFFFFF_t_70 8]  
原来是虚拟环境的问题，如果我们已经安装了模块，但是引用不到，需要我们耐心的查看一下是不是使用了，虚拟环境，或者是全局的环境的变量，使用：  
![在这里插入图片描述][20210612103116185.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyMzcwOTEz_size_16_color_FFFFFF_t_70 9]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyMzcwOTEz_size_16_color_FFFFFF_t_70 10]  
通过重新下载库，发现已经成功了  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyMzcwOTEz_size_16_color_FFFFFF_t_70 11]

#!/usr/bin/env python
    # _*_ coding: utf-8 _*_
    # @Time : 2021/6/12 10:05
    # @Author : zhaocunwei
    # @Version：V 0.1
    # @File : sqltest.py
    # @desc :
    
    from flask import Flask
    from flask_sqlalchemy import SQLAlchemy
    
    app = Flask(__name__)
    app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://root:root@127.0.0.1/test_flask'
    db = SQLAlchemy(app)
    
    class User(db.Model):
        __tablename__ = 'weibo_user'
        id = db.Column(db.Integer, primary_key=True)
        username = db.Column(db.String(64), nullable=False)
        password = db.Column(db.String(256), nullable=False)
        birth_date = db.Column(db.Date, nullable=True)
        age = db.Column(db.Integer, default=0)
    
    
    class UserAddress(db.Model):
        """ 用户的地址 """
        __tablename__ = 'weibo_user_addr'
        id = db.Column(db.Integer, primary_key=True)
        addr = db.Column(db.String(256), nullable=False)
        user_id = db.Column(db.Integer, db.ForeignKey('weibo_user.id'), nullable=False)
        user = db.relationship('User', backref=db.backref('address', lazy=True))

class UserAddress(db.Model):
        """ 用户的地址 """
        __tablename__ = 'weibo_user_addr'
        id = db.Column(db.Integer, primary_key=True)
        addr = db.Column(db.String(256), nullable=False)
        user_id = db.Column(db.Integer, db.ForeignKey('weibo_user.id'), nullable=False)
        user = db.relationship('User', backref=db.backref('address', lazy=True))
    
    
    @app.route('/')
    def mine():
        """  首页 """
        return render_template('index.html')
    
    
    @app.route('/user/<int:page>/')
    def list_user(page):
        """ 用户分页 """
        per_page = 10 # 每一页的数据大小
        # 1. 查询用户信息
        user_ls = User.query
        # 2. 准备分页的数据
        user_page_data = user_ls.paginate(page, per_page=per_page)
        return render_template('list_user.html', user_page_data=user_page_data)

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