Python3 MySQL 數(shù)據(jù)庫連接

數(shù)據(jù)庫連接

# 打開數(shù)據(jù)庫
db =pymysql.connnect("localhost","testuser","test123","TESTDB")

# 使用cursor() 方法創(chuàng)建一個游標(biāo)對象cursor
cursor = db.cursor()

# 使用execute() 方法執(zhí)行SQL查詢
cursor.execute("SELECT VERSION()")

#使用fetchone() 方法獲取單條數(shù)據(jù)
data = cursor.fetchone()

print("Database version: %s" % data)

#關(guān)閉數(shù)據(jù)庫連接
db.close()

創(chuàng)建數(shù)據(jù)庫表

import pymysql

# 打開數(shù)據(jù)庫
db =pymysql.connnect("localhost","testuser","test123","TESTDB")

# 使用cursor() 方法創(chuàng)建一個游標(biāo)對象cursor
cursor = db.cursor()

# 使用execute() 方法執(zhí)行SQL查詢
cursor.execute("DROP TABLE IF EXISTS EMPLOYEE")

# 使用預(yù)處理語句創(chuàng)建表
sql = """CREATE TABLE EMPLOYEE(
        FIRST_NAME CHAR(20) NOT NULL,
        LAST_NAME CHAR(20,
        AGE INT,
        SEX CHAR(1),
        INCOME FLOAT)"""

cursor.execute(sql)

#關(guān)閉數(shù)據(jù)庫連接
db.close()

數(shù)據(jù)庫插入操作

import pymysql

# 打開數(shù)據(jù)庫
db =pymysql.connnect("localhost","testuser","test123","TESTDB")

# 使用cursor() 方法創(chuàng)建一個游標(biāo)對象cursor
cursor = db.cursor()

# 使用execute() 方法執(zhí)行SQL查詢
cursor.execute("DROP TABLE IF EXISTS EMPLOYEE")

# 使用預(yù)處理語句創(chuàng)建表
sql = """(INSERT INTO EMPLOYEE(FIRST_NAME,
        LAST_NAME,AGE,SEX,INCOME)
        VALUES('MAC','Mohan', 20,'M',2000)"""
try:
    # 執(zhí)行sql語句
    cursor.execute(sql)
    # 提交到數(shù)據(jù)庫執(zhí)行
    db.commit()
except:
    # 如果發(fā)生錯誤則回滾
    db.rollback()


#關(guān)閉數(shù)據(jù)庫連接
db.close()

數(shù)據(jù)庫查詢操作

import pymysql

# 打開數(shù)據(jù)庫
db =pymysql.connnect("localhost","testuser","test123","TESTDB")

# 使用cursor() 方法創(chuàng)建一個游標(biāo)對象cursor
cursor = db.cursor()

# SQL 查詢語句
sql = "SELECT * FROM EMPLOYEE\
       WHERE INOCME > '%d'" % (1000)

try:
    #執(zhí)行SQL語句
    cursor.execute(sql)
    # 獲取所有記錄列表
    results = cursor.fetchall()
    for row in results:
        fname = row[0]
        lname = row[1]
        age = row[2]
        sex = row[3]
        income = row[4]
        # 打印結(jié)果
        print("fname=%s,lname=%s,age=%d,sex=%s,income=%d" % \
              (fname,lname,age,sex,income))
except:
    print("Error: unable to fetch data")
    

#關(guān)閉數(shù)據(jù)庫連接
db.close()

數(shù)據(jù)庫更新操作

import pymysql

# 打開數(shù)據(jù)庫
db =pymysql.connnect("localhost","testuser","test123","TESTDB")

# 使用cursor() 方法創(chuàng)建一個游標(biāo)對象cursor
cursor = db.cursor()


# SQL 更新語句
sql = "UPDATE EMPLOYEE SET AGE = AGE +1" \
      "WHERE SEX = '%c'" %('M')
                                                                
try:
    #執(zhí)行SQL語句
    cursor.execute(sql)
except:
    # 發(fā)生錯誤時回滾
    db.rollback()

#關(guān)閉數(shù)據(jù)庫連接
db.close()

刪除操作

import pymysql

# 打開數(shù)據(jù)庫
db =pymysql.connnect("localhost","testuser","test123","TESTDB")

# 使用cursor() 方法創(chuàng)建一個游標(biāo)對象cursor
cursor = db.cursor()


# SQL 刪除語句
sql = "DELETE FROM EMPLOYEE WHERE AGE > '%d'"  % (20)

try:
    #執(zhí)行SQL語句
    cursor.execute(sql)
except:
    # 發(fā)生錯誤時回滾
    db.rollback()

#關(guān)閉數(shù)據(jù)庫連接
db.close()