首先在linux上安装mysql
1 jason@t61:~$ mysql -u root 2 Welcome to the MySQL monitor. Commands end with ; or g. 3 Your MySQL connection id is 9 4 Server version: 5.6.24-0ubuntu2 (Ubuntu) 5 6 Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved. 7 8 Oracle is a registered trademark of Oracle Corporation and/or its 9 affiliates. Other names may be trademarks of their respective 10 owners. 11 12 Type 'help;' or 'h' for help. Type 'c' to clear the current input statement. 13 14 mysql> create database foo; 15 Query OK, 1 row affected (0.00 sec) 16 17 mysql> use foo ; 18 Database changed 19 mysql> exit 20 Bye
上面的代码是进入mysql创建数据库foo供测试
1 -这是create_children.sql的源码 2 create table children( 3 childno int(11) not null auto_increment, 4 fname varchar(30), 5 age int(11), 6 primary key (childno)); 7 8 INSERT INTO children VALUES (1,'Jenny',17); 9 INSERT INTO children VALUES (2,'Andrew',13); 10 INSERT INTO children VALUES (3,'Gavin',4); 11 INSERT INTO children VALUES (4,'Duncan',2); 12 INSERT INTO children VALUES (5,'Emma',0); 13 INSERT INTO children VALUES (6,'Alex',11); 14 INSERT INTO children VALUES (7,'Adrian',5);
在mysql中调用执行这段源码
1 mysql> source /home/jason/c_program/544977-blp3e/chapter08/create_children.sql 2 Query OK, 0 rows affected (0.48 sec) 3 4 Query OK, 1 row affected (0.08 sec) 5 6 Query OK, 1 row affected (0.03 sec) 7 8 Query OK, 1 row affected (0.12 sec) 9 10 Query OK, 1 row affected (0.11 sec) 11 12 Query OK, 1 row affected (0.05 sec) 13 14 Query OK, 1 row affected (0.06 sec) 15 16 Query OK, 1 row affected (0.05 sec) 17 18 mysql> show tables; 19 +---------------+ 20 | Tables_in_foo | 21 +---------------+ 22 | children | 23 +---------------+ 24 1 row in set (0.00 sec)
执行之后查看执行的效果：
1 mysql> select * from children; 2 +---------+--------+------+ 3 | childno | fname | age | 4 +---------+--------+------+ 5 | 1 | Jenny | 17 | 6 | 2 | Andrew | 13 | 7 | 3 | Gavin | 4 | 8 | 4 | Duncan | 2 | 9 | 5 | Emma | 0 | 10 | 6 | Alex | 11 | 11 | 7 | Adrian | 5 | 12 +---------+--------+------+ 13 7 rows in set (0.00 sec)
这样就完成数据库的准备工作
1 #include <stdlib.h> 2 #include <stdio.h> 3 4 #include "mysql.h" 5 6 int main(int argc, char *argv[]) 7 { 8 MYSQL *conn_ptr; 9 10 conn_ptr = mysql_init(NULL); 11 if (!conn_ptr) { 12 fprintf(stderr, "mysql_init failed "); 13 return EXIT_FAILURE; 14 } 15 16 conn_ptr = mysql_real_connect(conn_ptr, "localhost", "root", "","foo", 0, NULL, 0); 17 18 if (conn_ptr) { 19 printf("Connection success "); 20 } else { 21 printf("Connection failed "); 22 } 23 24 mysql_close(conn_ptr); 25 26 return EXIT_SUCCESS; 27 }
上面是初始化链接和建立链接的函数的使用
1 jason@t61:~/c_program/544977-blp3e/chapter08$ gcc -I/usr/include/mysql connect1.c -L/usr/lib/mysql -lmysqlclient -o connect1 2 connect1.c:4:19: fatal error: mysql.h: 没有那个文件或目录 3 #include "mysql.h" 4 ^ 5 compilation terminated. 6 //缺少头文件 7 jason@t61:~/c_program/544977-blp3e/chapter08$ sudo apt-get install mysql-devel 8 [sudo] password for jason: 9 正在读取软件包列表... 完成 10 正在分析软件包的依赖关系树 11 正在读取状态信息... 完成 12 E: 未发现软件包 mysql-devel 13 //不匹配uubuntu情况 14 jason@t61:/$ sudo apt-get install libmysqlclient-dev 15 正在读取软件包列表... 完成 16 正在分析软件包的依赖关系树 17 正在读取状态信息... 完成 18 下列【新】软件包将被安装： 19 libmysqlclient-dev 20 //成功
下面是编译这个代码：
1 jason@t61:~/c_program/544977-blp3e/chapter08$ gcc -I/usr/include/mysql connect1.c -L/usr/lib/mysql -lmysqlclient -o connect1 2 jason@t61:~/c_program/544977-blp3e/chapter08$ ./connect1 3 Connection failed
这个失败是因为原来的.c文件中的权限设置给的不合适
1 mysql> select user, host, password from mysql.user; 2 +------------------+-----------+-------------------------------------------+ 3 | user | host | password | 4 +------------------+-----------+-------------------------------------------+ 5 | root | localhost | | 6 | root | t61 | | 7 | root | 127.0.0.1 | | 8 | root | ::1 | | 9 | debian-sys-maint | localhost | *16AEF7D29C488DB8597DCBF25DCE8097E57558B7 | 10 +------------------+-----------+-------------------------------------------+ 11 5 rows in set (0.00 sec)
修改相应的账号或者密码：
1 jason@t61:~/c_program/544977-blp3e/chapter08$ gcc -I/usr/include/mysql connect1.c -L/usr/lib/mysql -lmysqlclient -o connect1 2 jason@t61:~/c_program/544977-blp3e/chapter08$ ./connect1 3 Connection success 4 jason@t61:~/c_program/544977-blp3e/chapter08$
1 #include <stdlib.h> 2 #include <stdio.h> 3 4 #include "mysql.h" 5 6 int main(int argc, char *argv[]) { 7 MYSQL my_connection; 8 9 mysql_init(&my_connection); 10 if (mysql_real_connect(&my_connection, "localhost", "root", "", "foo", 0, NULL, 0)) { 11 printf("Connection success "); 12 mysql_close(&my_connection); 13 } else { 14 fprintf(stderr, "Connection failed "); 15 if (mysql_errno(&my_connection)) { 16 fprintf(stderr, "Connection error %d: %s ", mysql_errno(&my_connection), mysql_error(&my_connection)); 17 } 18 } 19 20 return EXIT_SUCCESS; 21 }
这段代码有错误处理的能力可以把相应的错误信息打印出来：
1 //首先给错误的账号密码 2 jason@t61:~/c_program/544977-blp3e/chapter08$ gcc -I/usr/include/mysql connect2.c -L/usr/lib/mysql -lmysqlclient -o connect2 3 jason@t61:~/c_program/544977-blp3e/chapter08$ ./connect2 4 Connection failed 5 Connection error 1045: Access denied for user 'rick'@'localhost' (using password: YES) 6 jason@t61:~/c_program/544977-blp3e/chapter08$ gcc -I/usr/include/mysql connect2.c -L/usr/lib/mysql -lmysqlclient -o connect2 7 jason@t61:~/c_program/544977-blp3e/chapter08$ ./connect2 8 Connection success
//2015年06月28日 星期日 14时54分19秒