我如何向使用subprocess.POPEN打开的进程提供命令并检索o / p

Question

My requirement is that I need to start a sqlcmd process and then feed the sql statement to that process and retrieve the output generated in that scenario. Before you guys suggest me to use sql library to run sqlcmd let me tell you that I can't do that, I've a requirement to implement this using sqlcmd only.

here is my current code

from subprocess import Popen, PIPE

def ms_sql_session():
    IP = "xxxx"
    port = '1433'
    username = 'sa'
    password = 'abc'
    connString = 'sqlcmd -S tcp:%s,%s -dmaster -U%s -P%s ' %(IP, port, username, password)

    try:
        session = Popen(connString, stdin=PIPE, stdout=PIPE, stderr=PIPE)
        str_cmd = '''select @@version;
        go
        '''
        session.stdin.write(str_cmd)
        stdout, stderr = session.communicate()
        print stdout
        print stderr
        str_cmd = '''select @@version;
        go
        '''
        session.stdin.write(str_cmd)
        #stdout, stderr = session.communicate()
        print stdout
        print stderr
        str_cmd = '''select @@version;
        go'''
        session.stdin.write(str_cmd)
        #stdout, stderr = session.communicate()
        print stdout
        print stderr
        return True
    except Exception, e:
        print str(e)
        return False

ms_sql_session()

I'm trying to execute 3 statement and retrieve the o/p but i'm getting the exception at the second stdin.write operation

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Microsoft SQL Server 2005 - 9.00.5000.00 (Intel X86) 
    Dec 10 2010 10:56:29 
    Copyright (c) 1988-2005 Microsoft Corporation
    Developer Edition on Windows NT 5.2 (Build 3790: Service Pack 2)


(1 rows affected)


I/O operation on closed file

this is the output of my code.

Answer 1

Why do you want to use a system cmd for that? I would recommend to use an SQL library for that...