python中flask-mysqldb库用法详解

        Flask-MySQLdb是一个Flask扩展，可用于在Flask应用程序中使用MySQL数据库。它提供了一些方便的方法和功能，以便在Flask应用程序中轻松地连接和操作MySQL数据库。

1、安装Flask-MySQLdb库

pip install flask-mysqldb

注意：在Windows系统中直接安装即可，亲测在Centos7系统中安装失败，所需要的依赖没有安装成功，可以使用pymysql库代替此库。 

2、导入Flask-MySQLdb库

在Flask应用程序中导入Flask-MySQLdb库：

from flask_mysqldb import MySQL

3、配置MySQL数据库连接

在Flask应用程序中配置MySQL数据库连接：

app.config['MYSQL_HOST'] = 'localhost' # MySQL主机地址
app.config['MYSQL_USER'] = 'username' # MySQL用户名
app.config['MYSQL_PASSWORD'] = 'password' # MySQL密码
app.config['MYSQL_DB'] = 'database' # MySQL数据库名

4、初始化MySQL对象

在Flask应用程序中初始化MySQL对象：

mysql = MySQL(app)

5、使用MySQL对象查询数据

使用MySQL对象的cursor方法执行SQL查询并获取数据：

cur = mysql.connection.cursor()
cur.execute("SELECT * FROM users")
data = cur.fetchall()

6、使用MySQL对象插入数据

使用MySQL对象的cursor方法执行SQL插入操作：

cur = mysql.connection.cursor()
cur.execute("INSERT INTO users (name, email) VALUES (%s, %s)", ("John", "[email protected]"))
mysql.connection.commit()

7、关闭MySQL连接

使用MySQL对象的close方法关闭MySQL连接：

mysql.connection.close()

8、Flask框架应用flask-mysqldb库

示例代码：

from flask import Flask, request, jsonify
from flask_mysqldb import MySQL


app = Flask(__name__)
app.config['MYSQL_HOST'] = "39.xx.58.xx"
app.config['MYSQL_USER'] = "root"
app.config['MYSQL_PASSWORD'] = "dxxxxx"
app.config['MYSQL_DB'] = "flxxxxx"
mysql = MySQL(app)


@app.route("/users", methods=["GET"])
def get_all_users():
    query = request.args.get("query", None)
    pagenum = request.args.get("pagenum", 1)
    pagesize = request.args.get("pagesize", 5)
    if not query:
        cur = mysql.connection.cursor()
        cur.execute(f'SELECT * FROM users limit {(int(pagenum) - 1) * int(pagesize)}, {pagesize}')
        datas = cur.fetchall()
        cur.execute(
            f"SELECT count(*) FROM users")
        total = cur.fetchall()
        if total:
            total = total[0][0]
        else:
            total = 0
        datas_list = []
        for data in datas:
            dic = {"id": data[0], "username": data[1], "password": data[2], "age": data[3], "create_time": data[4], "role_name": data[5], "mobile": data[6], "email": data[7], "mg_state": data[8]}
            if dic.get('mg_state') == 1:
                dic['mg_state'] = True
            else:
                dic['mg_state'] = False
            datas_list.append(dic)
        cur.close()
        return jsonify({"meta": {'msg': 'success', 'status': 200}, "data": {"users": datas_list, "total": total, "pagenum": pagenum}})
    else:
        cur = mysql.connection.cursor()
        cur.execute(f"SELECT * FROM users where username like '%{query}%' limit {(int(pagenum) - 1) * int(pagesize)}, {pagesize}")
        datas = cur.fetchall()
        cur.execute(
            f"SELECT count(*) FROM users where username like '%{query}%'")
        total = cur.fetchall()
        if total:
            total = total[0][0]
        else:
            total = 0
        datas_list = []
        for data in datas:
            dic = {"id": data[0], "username": data[1], "password": data[2], "age": data[3], "create_time": data[4],
                   "role_name": data[5], "mobile": data[6], "email": data[7], "mg_state": data[8]}
            if dic.get('mg_state') == 1:
                dic['mg_state'] = True
            else:
                dic['mg_state'] = False
            datas_list.append(dic)
        cur.close()
        return jsonify({"meta": {'msg': 'success', 'status': 200},
                        "data": {"users": datas_list, "total": total, "pagenum": pagenum}})


@app.route('/users', methods=['POST'])
def add_user():
    json_data = request.get_json()
    username = json_data.get('username')
    password = json_data.get('password')
    age = json_data.get('age')
    create_time = json_data.get('create_time')
    role_name = json_data.get('role_name')
    mobile = json_data.get('mobile')
    email = json_data.get('email')
    cur = mysql.connection.cursor()
    cur.execute('INSERT INTO users (username, password, age, create_time, role_name, mobile, email) '
                'VALUES (%s, %s, %s, %s, %s, %s, %s)', (username, password, age, create_time, role_name, mobile, email))
    mysql.connection.commit()
    cur.close()
    data = json_data
    return jsonify({"meta": {'msg': 'success', 'status': 200}, "data": data})


@app.route('/users/<int:id>', methods=['PUT'])
def update_user(id):
    json_data = request.get_json()
    mobile = json_data.get('mobile')
    email = json_data.get('email')
    cur = mysql.connection.cursor()
    cur.execute('UPDATE users SET mobile=%s, email=%s WHERE id=%s', (mobile, email, id))
    mysql.connection.commit()
    cur.close()
    return jsonify({"meta": {'msg': 'success', 'status': 200}, "data": json_data})


@app.route('/users/<int:id>', methods=['DELETE'])
def delete_user(id):
    cur = mysql.connection.cursor()
    cur.execute('DELETE FROM users WHERE id=%s', (id,))
    mysql.connection.commit()
    cur.close()
    data = ""
    return jsonify({"meta": {'msg': '删除成功', 'status': 200}, "data": data})


if __name__ == '__main__':
    app.run()

运行结果：

GET：

POST：

PUT：

DELETE：