Python練習之操作MySQL數(shù)據(jù)庫

更新時間：2022年06月13日 11:12:04 作者：??孤寒者????

這篇文章主要介紹了Python練習之操作MySQL數(shù)據(jù)庫，文章通過如何創(chuàng)建MySQL數(shù)據(jù)表？如何向MySQL表中插入數(shù)據(jù)？如何查詢MySQL中的數(shù)據(jù)？的三個問題展開了詳細的內容介紹

一、創(chuàng)建MySQL數(shù)據(jù)表

# coding=utf-8
from pymysql import *
def connectDB():
    '''
    連接本地MySQL數(shù)據(jù)庫，指定連接的庫為test庫。
    :return:
    '''
    db = connect(host='localhost', user='root', password='123456', port=3306, db='test')
    return db
db = connectDB()
print(type(db))
def createTable(db):
    c = db.cursor()
    try:
        c.execute('''create table persons
                    (id int primary key not null,
                    name text not null,
                    age int not null,
                    address char(100),
                    salary real);''')
        db.commit()
        db.commit()
        return True
    except:
        db.rollback()
    return False
if createTable(db):
    print('create table success')
else:
    print('create table failed')

使用navicat工具查看：

三、向MySQL表中插入數(shù)據(jù)

# coding=utf-8
from pymysql import *
def connectDB():
    '''
    連接本地MySQL數(shù)據(jù)庫，指定連接的庫為test庫。
    :return:
    '''
    db = connect(host='localhost', user='root', password='123456', port=3306, db='test')
    return db
db = connectDB()
print(type(db))
def insertRecords(db):
    cursor = db.cursor()
    try:
        cursor.execute("delete from persons")
        cursor.execute('''
        insert into persons(id,name,age,address,salary)
        values(1, 'GuHanZhe', 18, 'China', 9999)
        ''')
        cursor.execute('''
        insert into persons(id,name,age,address,salary)
        values(2, 'XiaoZhang', 55, 'China', 9)
        ''')
        db.commit()
        return True
    except Exception as e:
        print(e)
        db.rollback()
    return False
if insertRecords(db):
    print("成功插入記錄")
else:
    print("插入記錄失敗")

使用navicat工具查看：

三、查詢MySQL中的數(shù)據(jù)

# coding=utf-8
from pymysql import *
def connectDB():
    '''
    連接本地MySQL數(shù)據(jù)庫，指定連接的庫為test庫。
    :return:
    '''
    db = connect(host='localhost', user='root', password='123456', port=3306, db='test')
    return db
db = connectDB()


def selectRecords(db):
    cursor = db.cursor()
    sql = 'select name,age,salary from persons order by age desc'
    cursor.execute(sql)
    results = cursor.fetchall()
    print(results)
    print(type(results))    # 打印發(fā)現(xiàn)是元組類型

selectRecords(db)
db.close()

我們發(fā)現(xiàn)查詢數(shù)據(jù)輸出類型是元組類型，如果我們想要將字段名和查詢出的數(shù)據(jù)一一對應該怎么做呢？
這里就需要用到兩個很常用的函數(shù)dict()和zip()，如下：

# coding=utf-8
import json
from pymysql import *
def connectDB():
    '''
    連接本地MySQL數(shù)據(jù)庫，指定連接的庫為test庫。
    :return:
    '''
    db = connect(host='localhost', user='root', password='123456', port=3306, db='test')
    return db
db = connectDB()


def selectRecords(db):
    cursor = db.cursor()
    sql = 'select name,age,salary from persons order by age desc'
    cursor.execute(sql)
    results = cursor.fetchall()
    print(results)
    print(type(results))    # 打印發(fā)現(xiàn)是元組類型

    # 將字段名和查詢結果整合在一起
    fields = ['name', 'age', 'salary']
    records = []
    for row in results:
        records.append(dict(zip(fields, row)))
    return json.dumps(records)      # 輸出類型為JSON字符串
endresults = selectRecords(db)
print(endresults)
db.close()