如何使用 freeTDS 和 unixODBC 配置 pyodbc 以正确接受来自 SQL Server 的字符串?

我无法将有效的字符串从 MSSQL 服务器获取到 Python 中.我相信某处存在编码不匹配.我相信它在 ODBC 层和 python 之间，因为我能够在 tsql 和 isql 中获得可读的结果.

I can not get a valid string from an MSSQL server into python. I believe there is an encoding mismatch somewhere. I believe it is between the ODBC layer and python because I am able to get readable results in tsql and isql.

pyodbc 期望什么字符编码?我需要在链中进行哪些更改才能使其正常工作?

What character encoding does pyodbc expect? What do I need to change in the chain to get this to work?

具体例子

这里以一个简化的python脚本为例:

Here is a simplified python script as an example:

#!/usr/bin/env python
import pyodbc

dsn = 'yourdb'
user = 'import'
password = 'get0lddata'
database = 'YourDb'

def get_cursor():
    con_string = 'DSN=%s;UID=%s;PWD=%s;DATABASE=%s;' % (dsn, user, password, database)
    conn = pyodbc.connect(con_string)
    return conn.cursor()

if __name__ == '__main__':
    c = get_cursor()
    c.execute("select id, name from recipe where id = 4140567")

    row = c.fetchone()
    if row:
        print row

这个脚本的输出是:

(Decimal('4140567'), u'\U0072006f\U006e0061\U00650067')

或者，如果脚本的最后一行改为:

Alternatively, if the last line of the script is changed to:

print "{0}, '{1}'".format(row.id, row.name)

那么结果是:

Traceback (most recent call last):
  File "/home/mdenson/projects/test.py", line 20, in <module>
    print "{0}, '{1}'".format(row.id, row.name)
UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-2: ordinal not in range(128)

使用 tsql 执行相同查询的脚本:

A transcript using tsql to execute the same query:

root@luke:~# tsql -S cmw -U import -P get0lddata
locale is "C"
locale charset is "ANSI_X3.4-1968"
using default charset "UTF-8"
1> select id, name from recipe where id = 4140567
2> go
id      name
4140567 orange2
(1 row affected)

以及isql:

root@luke:~# isql -v yourdb import get0lddata
SQL>  select id, name from recipe where id = 4140567
+----------------------+--------------------------+
| id                   | name                     |
+----------------------+--------------------------+
| 4140567              | orange2                  |
+----------------------+--------------------------+
SQLRowCount returns 1
1 rows fetched

所以我早上一直在研究这个，看起来高高低低，还没有弄清楚哪里出了问题.

So I have worked at this for the morning and looked high and low and haven't figured out what is amiss.

详情

以下是版本详情:

• 客户端是 Ubuntu 12.04
• freetds v0.91
• unixodbc 2.2.14
• python 2.7.3

• pyodbc 2.1.7-1(来自 ubuntu 包)&3.0.7-beta06(从源代码编译)

• Client is Ubuntu 12.04
• freetds v0.91
• unixodbc 2.2.14
• python 2.7.3

• pyodbc 2.1.7-1 (from ubuntu package) & 3.0.7-beta06 (compiled from source)

服务器是 XP 和 SQL Server Express 2008 R2

Server is XP with SQL Server Express 2008 R2

这里是客户端的几个配置文件的内容.

Here are the contents of a few configuration files on the client.

/etc/freetds/freetds.conf

/etc/freetds/freetds.conf

[global]
    tds version = 8.0
    text size = 64512
[cmw]
    host = 192.168.90.104
    port = 1433
    tds version = 8.0
    client charset = UTF-8

/etc/odbcinst.ini

/etc/odbcinst.ini

[FreeTDS]
Description = TDS driver (Sybase/MS SQL)
Driver = /usr/lib/x86_64-linux-gnu/odbc/libtdsodbc.so
Setup = /usr/lib/x86_64-linux-gnu/odbc/libtdsS.so
CPTimeout =
CPReuse =
FileUsage = 1

/etc/odbc.ini

/etc/odbc.ini

[yourdb]
Driver = FreeTDS
Description = ODBC connection via FreeTDS
Trace = No
Servername = cmw
Database = YourDB
Charset = UTF-8