Windows上的MySQL UDF开发

曾以为Windows版本的MySQL存在不能使用UDF的BUG诸提交了一个bug报告。不过似乎发现是我搞错了，MySQL的技术支持人员给了非常完美的解答，同大家分享一下。下边是原文回复 :)
Sorry this isn't a bug.Below I pasted a sample I did sometime ago for another user:
Ok. Assuming you have VC++ and the source distribution and a serverrunning,I will create a UDF that returns a name:
Note: the sample is ugly, but the purpose here is to show you howto handle the UDF.
- Open the mysqld.dsw workspace.- Add New project to the workspace- Project name: my_udf- Select Win32 Dynamic-Link Library- Click OK- Select An Empty DLL project- Click Finish- Click OK- Add a new file called my_udf.cpp to the project:
#include <stdlib.h>#include <winsock.h>#include <mysql.h>
extern "C" {char *my_name(UDF_INIT *initid, UDF_ARGS *args, char *is_null,       char *error);}
char *my_name(UDF_INIT *initid, UDF_ARGS *args, char *is_null,       char *error){    char * me = "my name";
    return me;}
- Type Ctrl+N for to create a new file.- Select text type- File name: my_udf.def- Edit the above file with the below contents:LIBRARY         UDF_EXAMPLEDESCRIPTION             'Example Using UDF with VC++'VERSION         1.0EXPORTS        my_name
- Right Click the my_udf project and select Settings- Click the C/C++ tab- Select General in the Category Combo- Add the macro HAVE_DLOPEN to the PreProcessor definition- Select Preprocessor in the Category Combo- Add the include path to the text box: Additional Include directories  e.g: ../include- Press F7 for to build the DLL.
- Copy the my_udf.dll to the environment path directory:  \winnt\system32 for example.
- Start the mysql client and issue:
C:\mysql-udf\bin>mysql -uroot -pEnter password:Welcome to the MySQL monitor.  Commands end with ; or \g.Your MySQL connection id is 2 to server version: 3.23.52-max-nt
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> CREATE FUNCTION my_name RETURNS STRING SONAME "my_udf.dll";Query OK, 0 rows affected (0.08 sec)
mysql> select my_name();
mysql> drop function my_name;Query OK, 0 rows affected (0.00 sec)
画蛇添足的作下简要中文说明。
抱歉，这并不是一个bug。下面我粘贴一个以前为某个客户做的简例，假设你有了VC++,源码分发，并且有一个正常运行的MySQL服务器。
我将创建一个UDF它将一个名字：注意：例子非常简陋，目的是让你了解该如何处理手头的UDF。
- 打开 mysqld.dsw 工作区。- 添加新项目到这个工作区- Project name: my_udf            // 项目名称:my_udf- 选择 Win32 Dynamic-Link Library // Win32动态连接库- 点击 OK- 选择 An Empty DLL project       // 一个空DLL项目- 点击 Finish- 点击 OK- 添加新文件 my_udf.cpp 到项目中:#include <stdlib.h>#include <winsock.h>#include <mysql.h>
extern "C" {char *my_name(UDF_INIT *initid, UDF_ARGS *args, char *is_null,       char *error);// 兼容C}
char *my_name(UDF_INIT *initid, UDF_ARGS *args, char *is_null,       char *error){    char * me = "my name";
    return me;    // 调用此UDF将返回 my name}- 按 Ctrl+N 来创建一个新文件。- 选择 text 类型- File name: my_udf.def file://文件名：my_udf.def- 按照下边的内容编辑文件。LIBRARY         UDF_EXAMPLEDESCRIPTION             'Example Using UDF with VC++'VERSION         1.0EXPORTS        my_name
- 右击my_udf项目并选择Settings- 点 C/C++ 选项卡- 选择 General- 添加宏 HAVE_DLOPE 到预处理器定义- 选择 Preprocessor- 添加头文件路径: Additional Include directories  例如: ../include- 按 F7 去编译成 DLL.
- 复制 my_udf.dll 到环境变量path定义过的目录  比如 \winnt\system32 。
- 打开mysql客户端
C:\mysql-udf\bin>mysql -uroot -pEnter password:Welcome to the MySQL monitor.  Commands end with ; or \g.Your MySQL connection id is 2 to server version: 3.23.52-max-nt
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql> CREATE FUNCTION my_name RETURNS STRING SONAME "my_udf.dll";Query OK, 0 rows affected (0.08 sec)
mysql> select my_name();
mysql> drop function my_name;Query OK, 0 rows affected (0.00 sec)
ok!欢迎大家来MySQL板交流UDF设计经验！我的电子邮件是HeartIcy@163.com，手机13706410308。同时，我们MySQL板准备开始系统化持续性翻译MySQL文档，希望大家多多支持共同完成这一项目。
HeartIcy2003年5月17日于中国济南