Linux-MySql

MySql

1:连接

1 #include <mysql.h>
2 MYSQL *mysql_init(MYSQL *);
3 MYSQL *mysql_real_connect(MYSQL *connection,const char *server_host,......);
4 void mysql_close(MYSQL *connection);
5 int mysql_options(MYSQL* connection, enum option_to_set const char* argument);

2:错误处理
- 1 //错误处理函数
- 2 unsigned int mysql_errno(MYSQL *connection);
- 3 char *mysql_error(MYSQL *connection);

3:执行SQL语句

1 //success 0
2 int mysql_query(MYSQL *connection, const char *query); 
3 my_ulonglong mysql_affected_rows(MYSQL *connection);

4.返回数据的语句

//一次提取所有的数据
MYSQL_RES *mysql_store_result(MYSQL *connection);
//返回记录的条目
my_ulonglong mysql_num_rows(MYSQL_RES* result);
//从mysql_store_result中得到的结构中提取一行
MYSQL_ROW mysql_fetch_row(MYSQL_RES *result);
//在结果集中跳转，设置将被下一个mysql_fetch_row操作返回的行
void mysql_data_seek(MYSQL_RES *result,my_ulonglong offset);
//返回一个偏移值，不是行号，不能用于mysql_data_seek
MYSQL_ROW_OFFSET mysql_row_tell(MYSQL_RES *result);
//在结果集中移动当前位置，并返回之前的位置
MYSQL_ROW_OFFSET mysql_row_seek(MYSQL_RES *result,MYSQL_ROW_OFFSET offset);
//清理结果集
void mysql_free_result(MYSQL_RES *result);

5.处理返回的数据

1 //MySQL返回两种类型的数据，列数据和元数据
2 
3 //查询结果的基本信息，返回结果集中的字段（列）数目
4 unsigned int mysql_field_count(MYSQL *connection);

Example

 1 #include <stdlib.h>
 2 #include <stdio.h>
 3 
 4 #include "mysql.h"
 5 
 6 MYSQL my_connection;
 7 MYSQL_RES *res_ptr;
 8 MYSQL_ROW sqlrow;
 9 
10 void display_row()
11 {
12     unsigned int field_count;
13     field_count = 0;
14     while(field_count < mysql_field_count(&my_connection))
15     {
16         printf("%s ",sqlrow[field_count]);
17         field_count++;
18     }
19     printf("
");
20 }
21 int main(int argc, char *argv[])
22 {
23     int res;
24     
25     mysql_init(&my_connection);
26     if(mysql_real_connect(&my_connection,"localhost","rick","secret","foo",0,NULL,0))
27     {
28         printf("Connection success
");
29         res = mysql_query(&my_connection,"select childno, fname,age from children where age > 5");
30         if(res)
31         {
32             printf("select error:%s
",mysql_error(&my_connection));
33         }
34         else
35         {
36             res_ptr = mysql_store_result(&my_connection);
37             if(res_ptr)
38             {
39                 printf("Retrieved %lu rows
",(unsigned long)mysql_num_rows(res_ptr));
40                 while((sqlrow = mysql_fetch_row(res_ptr)))
41                 {
42                     printf("Fetched data...
");
43                     display_row();
44                 }
45                 if(mysql_errno(&my_connection))
46                 {
47                     fprintf(stderr,"Retrive error:%s
",mysql_error(&my_connection));
48                 }
49                 mysql_free_result(res_ptr);
50             }
51         }
52         mysql_close(&my_connection);
53     }
54     else
55     {
56         fprintf(stderr,"Connection failed
");
57         if(mysql_errno(&my_connection))
58         {
59             fprintf(stderr,"Connection error %d:%s
",mysql_error(&my_connection));
60         }
61     }
62     return EXIT_SUCCESS;
63 }

编译：
- 　首先查看mysql.h的安装位置
  - locate mysql.h
  - g++ main.cpp MysqlHelper.cpp -I /usr/local/mysql/include/ -L /usr/local/mysql/lib/ -lmysqlclient