#!/usr/bin/python3
#导入数据库
import pymysql
# 打开数据库连接
db = pymysql.connect("localhost", "root", "123456", "test")
# 使用 cursor() 方法创建一个游标对象 cursor
cursor = db.cursor()
# 使用 execute() 方法执行 SQL 查询
cursor.execute("SELECT VERSION()")
# 使用 fetchone() 方法获取单条数据.
data = cursor.fetchone()
print("Database version : %s " % data)
# 关闭数据库连接
db.close()
#使用预处理语句创建表
sql = """create table emp(
FIRST_NAME CHAR(20) NOT NULL,
LAST_NAME CHAR (20),
AGE INT ,
SEX CHAR (1),
INCOME FLOAT ) """
#导入数据
import pymysql
#打开数据库连接
db = pymysql.connect("localhost","root","123456","test")
#使用cursor()方法创建一个游标对象cursor
cursor = db.cursor()
#使用execute()方法执行SQL,如果存在则和删除
#cursor.execute("drop table if EXISTS emp")
#创建数据表
#cursor.execute("create table emp(FIRST_NAME CHAR (20) NOT NULL ,LAST_NAME varchar(20),AGE INT ,SEX CHAR (1),INCOME FLOAT)")
#插入数据
sql = """INSERT INTO emp (FIRST_NAME,LAST_NAME,AGE,SEX,INCOME)
VALUES ('Mac','Mohan',20,'M',2000)
"""
try:
#执行sql语句
cursor.execute(sql)
# 执行sql语句
db.commit()
except:
#发生错误时回滚
db.rollback()
#关闭数据库
db.close()
#查询emp表工资大于1000的员工信息
#导入数据
import pymysql
#打开数据库连接
db = pymysql.connect("localhost","root","123456","test")
#使用cursor()方法创建一个游标对象cursor
cursor = db.cursor()
#SQL查询语句
sql = "SELECT * FROM emp WHRER INCOME > 1000 "
try:
cursor.execute(sql)
results = cursor.fetchall()
for row in results:
fname = row[0]
lname = row[1]
age = row[2]
sex = row[3]
income = row[4]
print("fname = %s,lname = %s,age = %d,sex = %s,income = %d" ,fname,lname,age,sex,income)
except:
print("error")
db.close()
import pymysql
# 打开数据库连接
db = pymysql.connect("localhost", "root", "123456", "test")
# 使用cursor()方法获取操作游标
cursor = db.cursor()
# SQL 查询语句
sql = "SELECT * FROM emp \
WHERE INCOME > '%d'" % (1000)
try:
# 执行SQL语句
cursor.execute(sql)
# 获取所有记录列表
results = cursor.fetchall()
for row in results:
fname = row[0]
lname = row[1]
age = row[2]
sex = row[3]
income = row[4]
# 打印结果
print("fname=%s,lname=%s,age=%d,sex=%s,income=%d" % \
(fname, lname, age, sex, income))
except:
print("Error: unable to fetch data")
# 关闭数据库连接
db.close()
#类、面向对象
class MyClass():
i = 123456
def f(self):
return 'hello world'
#实例化类
x = MyClass()
#访问类的属性和方法
print("MyClass 类的属性i为:",x.i)
print("MyClass 类的方法f输出为:",x.f())
class Comp:
def __init__(self,realpart,imagpart):
self.r = realpart
self.i = imagpart
x = Comp(3.0,-4.5)
print(x.r,x.i)
class Test:
def prt(self):
print(self)
print(self.__class__)
t = Test()
t.prt()
#定义一个人的类,定义名字年龄为 基本属性,体重为私有属性
class people:
name = ''
age = 0
__weight = 0
def __init__(self,n,a,w):
self.name = n
self.age = a
self.__weight = w
def speak(self):
print("%s 说:我 %d 岁" %(self.name,self.age))
#print("%s 说:我 %d 岁" %(self.name,self.age))中间不需要加标点符号
#实例化类
p = people('lili',20,56)
p.speak()