Question

由于查询返回的结果超过1，因此在Get_results类中如何将data_out作为数组返回以迭代查询结果？

import psycopg2
import sys

class Get_results():
    def db_call(self,query,dbHost,dbName,dbUser,dbPass):
        try:
            con = None
            con = psycopg2.connect(host=dbHost, database=dbName,
                                   user=dbUser, password=dbPass)
            cur = con.cursor()
            cur.execute(query)
            data = cur.fetchall()
            for data_out in data:
                return data_out
        except psycopg2.DatabaseError, e:
                print 'Error %s' % e
                sys.exit(1)
        finally:
            if con:
                con.close()

 sql = " some sql "
 w = Get_results()
 for i in  w.db_call(sql, dbHost, dbName, dbUser, dbPass):
     print "The result is : " + i

对于附加信息，如果我在print data之后立即添加data = cur.fetchall()，我会得到结果：

[('The_Galaxy', 'The_Galaxy:star'),
 ('The_Galaxy', 'The_Galaxy:planet')]

Answer 1

直接的答案是改变：

for data_out in data:
    data_out result

为：

for data_out in data:
    yield data_out

但是你应该看一下使用with语句（如果DB API支持它），并简化代码 - 这可以通过生成一个生成器函数来完成（类是OTT）

Answer 2

import psycopg2
import sys

class Get_results():
    def db_call(self,query,dbHost,dbName,dbUser,dbPass):
        try:
            con = None
            con = psycopg2.connect(host=dbHost, database=dbName,
                                   user=dbUser, password=dbPass)
            cur = con.cursor()
            cur.execute(query)
            data = cur.fetchall()  
            resultList = []  
            for data_out in data:  
                resultList.append(data_out[1])  


            return resultList   
        except psycopg2.DatabaseError, e:
                print 'Error %s' % e
                sys.exit(1)
        finally:
            if con:
                con.close()

 sql = " some sql "
 w = Get_results()
 for i in  w.db_call(sql, dbHost, dbName, dbUser, dbPass):
     print "The result is : " + i

将SQL结果从函数返回为数组

2 个答案: