在Windows上的MySQL UDF开发应用
| 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。 用户你好。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 #include #include 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_EXAMPLE DESCRIPTION 'Example Using UDF with VC++' VERSION 1.0 EXPORTS 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 -p Enter 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) 以下是MySQL技术人员的回信原文： 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 server running, I will create a UDF that returns a name: Note: the sample is ugly, but the purpose here is to show you how to 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 #include #include 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_EXAMPLE DESCRIPTION 'Example Using UDF with VC++' VERSION 1.0 EXPORTS 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 -p Enter 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)
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