c / c + + 调用mysql存储过程

原文：c / c + + call mysql stored procedure

1、首先创建一个表用于存储用户信息

Create table student(
      id int auto_increment,
      name varchar(20),
      age tinyint,
      remark varchar(50),
       primary key(id)
);

2、插入几条用户信息

Insert into student values(1,"zhouys",90, "");
commit;

3、查看刚刚插入的用户信息

mysql> select * from student;
+------+-----------+------+----------+
| id   | name   | age | remark |
+------+-----------+------+----------+
|    1 | zhouys |   90 |        |
+------+-----------+------+-----------+
1 row in set (0.00 sec)
 
mysql>

4、创建存储过程

delimiter //
 
create procedure querystudent(
       in in_id int ,   #0- Character ID 1-digital id    
       #
       out out_ret int,                # Returns the result 
       out out_name varchar(20),        # First name 
       out out_age   int                # Age     
)
label_a:begin
       declare v_name varchar(20) ;
       declare v_age tinyint ;
       # Parameters determine 
       if (in_id<=0) then
              set out_ret=-1; #id error
              leave label_a;
       end if;
             
       SELECT name,age into v_name,v_age from student where't found
              leave label_a;
       end if;    
             
       set out_ret=0;
       set out_name=v_name;
       set out_age=v_age;
end;
//
delimiter ;

5、C语言调用存储过程的方法步骤：

5.1、Mysql 的句柄初始化

if(!mysql_init(&mysql))
       {
              printf("mysql_init failed!\n");
              return 0;
       }

5.2、连接到MySQL数据库

//login or connect
       if(!mysql_real_connect(&mysql,"localhost","root","","billingdb",0,NULL,CLIENT_MULTI_STATEMENTS))
       {
              printf("mysql_real_connect() failed!\n");
              mysql_close(&mysql);
              return 0;
       }

5.3、调用存储过程

//call
       strcpy(query,"call querystudent (1,@ret,@ out_name,@ out_age)");
       printf("query sql=[%s]\n",query);
    ret= mysql_real_query(&mysql,query,(unsigned int)strlen(query));

5.4、查询返回值及输出参数值

mysql_query(&mysql, "SELECT @ret,@ out_name,@ out_age ");
 
       //get result
       if (ret)
    {
              printf("Error exec query: %s\n",mysql_error(&mysql));
    }
    else
       {
              printf("[%s] exec...\n", query);
    }
 
       results = mysql_store_result(&mysql);

5.5、获取结果值

while((record = mysql_fetch_row(results))) {
              printf("[%s]-[%s]-[%s]\n", record[0], record[1],record[2]);
       }

5.6、释放资源和mysql连接句柄

mysql_free_result(results);
mysql_close(&mysql);

6、结论

Mysql的存储过程可以实现相当强大的功能，这里只是一些基本的用法，希望能给你一些帮助。也欢迎分享......

7、个人使用经验心得

像C#调用都可以绑定输出参数，直接通过输出参数得到值，但是c++中使用prepare绑定输出参数，却返回以下错误信息：

Error Code: 1414. OUT or INOUT argument 2 for routine knockout_dbo.ko_SignUpYoungBoxer is not a variable or NEW pseudo-variable in BEFORE trigger

以下链接是找到的相关问题讨论：

http://forums.mysql.com/read.php?38,505961

http://bugs.mysql.com/bug.php?id=25970

下面是一个c++的MySQL封装

http://tangentsoft.net/mysql++/