python连接sqlserver和MySQL实现增删改查

参考python核心编程

编写一个用户洗牌的脚本，根据用户输入，选择连接sqlserver或者MySQL，创建数据库、表，随机生成数据，并实现增删改查。

其中，为了兼容python2和python3，统一了打印函数、录入函数、动态导包等

一些字段声明为全局变量，这样我们在后续的学习中，可以引用这些变量和函数。

ushuffle.py:

#python 3.6
#统一输出函数，使用distutils.log.warn()函数代替版本2中的print语句和版本3中的print函数
from distutils.log import warn as printf
from random import randrange
#检测内置函数中是否包括raw_input()，如果存在说明版本是2（或者1），不存在说明是3。这样的话，无论是哪个版本，最终scanf函数表示了该功能
if isinstance(__builtins__,dict) and \'raw_input\' in __builtins__:
    scanf = raw_input
elif hasattr(__builtins__,\'raw_input\'):
    scanf = raw_input
else:
    scanf = input

FIELDS = (\'login\',\'userid\',\'projid\')
COLSIZ = 10
RDBMSs = {\'s\':\'sql server\',\'m\':\'mysql\'}
DBNAME = \'test\'
DB_EXC = None
DBUSER = \'root\'
DBSERVER = \'127.0.0.1\'
NAMELEN = 10

tformat = lambda s: str(s).title().ljust(COLSIZ)#str().title()将单词首字母大写；ljust()左对齐，并使用空格填充直至达到指定长度
cformat = lambda s: s.upper().ljust(COLSIZ) #

def setup():
    return RDBMSs[scanf(\'\'\'
    请选择数据库类型：
    (Sql) Server
    (M)ySQL
    
    请键入：\'\'\').strip().lower()[0]]

def connect(db,DBNAME):
    global DB_EXC
    dbDir = \'%s_%s\' % (db,DBNAME)
    if db == \'mysql\':
        try:
            #python3.0以前的版本
            import MySQLdb
            import _mysql_exceptions as DB_EXC
            try:
                cxn = MySQLdb.connect(user = DBUSER,password = \'Jwxjs123456\',db=DBNAME)
            except DB_EXC.OperationalError:
                try:
                    cxn = MySQLdb.connect(user = DBUSER,password = \'Jwxjs123456\',db=DBNAME)
                    cxn.query(\'create database %s\' % DBNAME)
                    cxn.commit()
                    cxn.close()
                    cxn = MySQLdb.connect(db=DBNAME)
                except DB_EXC.OperationalError:
                    return None
        except ModuleNotFoundError: #ImportError
            try:
                #python3.0以上的版本
                import pymysql
                import pymysql.err as DB_EXC
                try:
                    cxn = pymysql.connect(**{\'host\':DBSERVER,\'database\':DBNAME,\'user\':DBUSER,\'password\':\'Jwxjs123456\'})
                except DB_EXC.InternalError:
                    #连接成功但是没有指定的数据库
                    cxn = pymysql.connect(**{\'host\':DBSERVER,\'user\':DBUSER,\'password\':\'Jwxjs123456\'})
                    cur = cxn.cursor()
                    cur.execute(\'create database %s;\' % DBNAME)
                    cxn.commit()
                    cxn = pymysql.connect(**{\'host\':DBSERVER,\'database\':DBNAME,\'user\':DBUSER,\'password\':\'Jwxjs123456\'})
            except ImportError:
                return None
    elif db == \'sql server\':
        import pymssql
        import _mssql
        #import pymssql.StandardError as DB_EXC
        try:
            cxn = pymssql.connect(**{\'server\':DBSERVER,\'database\':DBNAME,\'password\':\'Jwxjs123456\',\'user\':\'sa\'})
            printf(\'     成功链接数据库%s\' % DBNAME)
        except BaseException:
            #这里一定要设置为自动提交模式，否则创建数据库会失败
            cxn = pymssql.connect(**{\'server\':DBSERVER,\'password\':\'Jwxjs123456\',\'user\':\'sa\',\'autocommit\':True})
            
            cursor = cxn.cursor()
            cxn.commit()
            cursor.execute(\'create database %s;\' % DBNAME)
            #cxn.close()
            cxn = pymssql.connect(**{\'server\':DBSERVER,\'database\':DBNAME,\'password\':\'Jwxjs123456\',\'user\':\'sa\',\'autocommit\':True})
            printf(\'数据库%s 不存在，新建该数据库\' % DBNAME)
    return cxn

def create(cur):
    try:
        cur.execute(\'\'\'
            create table users(login varchar(%s),
                userid int,
                projid int
            )
        \'\'\' % NAMELEN)
        printf(\'……………新建users表成功\')
    except BaseException:
        drop(cur)
        create(cur)
        printf(\'       已存在表users,删除后并新建此表……………………\')
        
drop = lambda cur:cur.execute(\'drop table users\')

NAMES =(
    (\'arron\',8312),(\'angle\',7603),(\'dane\',7306),
    (\'jess\',7912),(\'jim\',7512),(\'larry\',7311),
)

def randName():
    pick = set(NAMES)#内置函数set()创建一个无序不重复元素集，可进行关系测试，删除重复数据，还可以计算交集、差集、并集等
    while pick:
        yield pick.pop()

def insert(cur,db):
    cur.executemany(\'insert into users values(%s,%s,%s)\',[(who,uid,randrange(1,5)) for who,uid in randName()])

#返回最后一次操作影响的行数，这里考虑右边对象是不是支持该属性，不支持的话则返回-1
getRC = lambda cur:cur.rowcount if hasattr(cur,\'rowcount\') else -1
    
    
def update(cur):
    fr = randrange(1,5)
    to = randrange(1,5)
    cur.execute(\'update users set projid = %s where projid = %s\' % (to,fr))
    return fr,to,getRC(cur)
    
def dbDump(cur):
    cur.execute(\'select * from users\')
    printf(\'\n%s\' % \'\'.join(map(cformat,FIELDS)))
    for data in cur.fetchall():
        printf(\'\'.join(map(tformat,data)))#join()将序列中的元素以指定的字符连接生成一个新的字符串。

def delete(cur):
    rm = randrange(1,5)
    cur.execute(\'delete from users where projid = %s\' % rm)
    return rm,getRC(cur)

drop = lambda cur:cur.execute(\'drop table users\')
    
    
def main():
    #用户选择数据库类型
    db = setup()
    printf(\'\n****将要连接到 %s(%s) 数据库****\' % (DBNAME,db))
    #创建数据库连接
    cxn = connect(db,DBNAME)
    if not cxn:
        printf(\'\n     连接数据库%s(%s) 失败，程序退出!!!\' % (DBNAME,db))
        return
    else:
        printf(\'\n    成功连接数据库%s(%s)    \' % (DBNAME,db))
    cur = cxn.cursor()
    printf(\'\n      创建 users表……\')
    create(cur)
    
    printf(\'\n*****初始化users表******\')
    insert(cur,db)
    dbDump(cur)
    
    printf(\'\n ***随机更改projid****\')
    fr,to,num = update(cur)
    printf(\'\t(%s 个用户被更改了) from (%s) to(%s)\' % (num,fr,to))
    dbDump(cur)
    
    printf(\'\n***随机删除某一组数据***\')
    rm,num = delete(cur)
    printf(\'\t(组%s中共%s个用户被删除了)\' % (rm,num))
    dbDump(cur)
    
    printf(\'\n*****删除users表*******\')
    drop(cur)

    if db == \'mysql\':
        cxn.commit() #sqlserver 的链接已经被设置为自动提交
    printf(\'\n    关闭数据库连接     \')
    cxn.close()
    
if __name__ == \'__main__\':
    main()

运行结果如下：