前提条件
本机安装MySQL 8 数据库
整体步骤
第一步:开启Windows 子系统安装Ubuntu 22.04.4,安装MySQL 数据库第三方库执行 如下命令:
sudo aptitude install libmysqlclient-dev
wz2012@LAPTOP-8R0KHL88:/mnt/e/vsCode/cpro$ sudo aptitude install libmysqlclient-dev
The following NEW packages will be installed:libmysqlclient-dev libmysqlclient21{a} libssl-dev{a} libzstd-dev{a} zlib1g-dev{a}
The following packages will be REMOVED:libssl1.1{u}
0 packages upgraded, 5 newly installed, 1 to remove and 10 not upgraded.
Need to get 5901 kB of archives. After unpacking 26.2 MB will be used.
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Get: 1 http://mirrors.aliyun.com/ubuntu jammy-security/main amd64 libmysqlclient21 amd64 8.0.37-0ubuntu0.22.04.3 [1302 kB]
Get: 2 http://mirrors.aliyun.com/ubuntu jammy-security/main amd64 libssl-dev amd64 3.0.2-0ubuntu1.15 [2376 kB]
Get: 3 http://mirrors.aliyun.com/ubuntu jammy/main amd64 libzstd-dev amd64 1.4.8+dfsg-3build1 [401 kB]
Get: 4 http://mirrors.aliyun.com/ubuntu jammy-security/main amd64 zlib1g-dev amd64 1:1.2.11.dfsg-2ubuntu9.2 [164 kB]
Get: 5 http://mirrors.aliyun.com/ubuntu jammy-security/main amd64 libmysqlclient-dev amd64 8.0.37-0ubuntu0.22.04.3 [1658 kB]
Fetched 5901 kB in 22s (271 kB/s)
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(Reading database ... 32523 files and directories currently installed.)
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Unpacking libmysqlclient-dev (8.0.37-0ubuntu0.22.04.3) ...
Setting up libmysqlclient21:amd64 (8.0.37-0ubuntu0.22.04.3) ...
Setting up libzstd-dev:amd64 (1.4.8+dfsg-3build1) ...
Setting up libssl-dev:amd64 (3.0.2-0ubuntu1.15) ...
Setting up zlib1g-dev:amd64 (1:1.2.11.dfsg-2ubuntu9.2) ...
Setting up libmysqlclient-dev (8.0.37-0ubuntu0.22.04.3) ...
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第二步:编写MySQL 8 数据库连接,验证数据是否能够正常联通。
温馨提示:相关重要说明,已经代码中进行标记。
mysql_demo.c
#include <mysql/mysql.h>
#include <stdio.h>
// MySQL 数据库连接
int main(void){// 数据库连接MYSQL *conn;// 数据库集合MYSQL_RES *res;// 数据库行记录MYSQL_ROW *row;char *server = "localhost";char *user = "root";char *password = "123456"; /* 此处改成你的密码 */char *database = "base";/*数据库,比如base*/conn = mysql_init(NULL);/* 数据库连接 */if (!mysql_real_connect(conn, server,user, password, database, 0, NULL, 0)) {fprintf(stderr, "%s\n", mysql_error(conn));exit(1);}printf("数据库连接成功");return 0;}
第三步:编译mysql_demo.c文件
我这里演示错误的编译方式/(使用常用代码编辑方式,这是一种错误方式)错误结果如下:
wz2012@LAPTOP-8R0KHL88:/mnt/e/ubuntu_code$ cd "/mnt/e/ubuntu_code/" && gcc mysql_demo.c -o mysql_demo && "/mnt/e/ubuntu_code/"mysql_demo
/usr/bin/ld: /tmp/ccm7ZrUH.o: in function `main':
mysql_demo.c:(.text+0x3e): undefined reference to `mysql_init'
/usr/bin/ld: mysql_demo.c:(.text+0x6b): undefined reference to `mysql_real_connect'
/usr/bin/ld: mysql_demo.c:(.text+0x80): undefined reference to `mysql_error'
collect2: error: ld returned 1 exit status
上述代码错误原因:没有找到mysql_init 函数定义的库文件/undefined reference to `mysql_init'。
解决办法:
使用mysql_config 命令查找MySQL 依赖的LIB库, --libs_r 就是我们需要添加编译mysql 库链接参数。
wz2012@LAPTOP-8R0KHL88:/mnt/e/ubuntu_code$ mysql_config
Usage: /usr/bin/mysql_config [OPTIONS]
Compiler: GNU 11.4.0
Options:--cflags [-I/usr/include/mysql ]--cxxflags [-I/usr/include/mysql ]--include [-I/usr/include/mysql]--libs [-L/usr/lib/x86_64-linux-gnu -lmysqlclient -lzstd -lssl -lcrypto -lresolv -lm]--libs_r [-L/usr/lib/x86_64-linux-gnu -lmysqlclient -lzstd -lssl -lcrypto -lresolv -lm]--plugindir [/usr/lib/mysql/plugin]--socket [/var/run/mysqld/mysqld.sock]--port [0]--version [8.0.37]--variable=VAR VAR is one of:pkgincludedir [/usr/include/mysql]pkglibdir [/usr/lib/x86_64-linux-gnu]plugindir [/usr/lib/mysql/plugin]
切换至Unbuntu 命令输出控制台输入如下编译指令:
wz2012@LAPTOP-8R0KHL88:/mnt/e/ubuntu_code$ gcc mysql_demo.c -o mysql_demo -L/usr/lib/x86_64-linux-gnu -lmysqlclient -lzstd -lssl -lcrypto -lresolv -lm
第四步:测试MySQL 数据库是否联通,遇到的问题总结
1、问题1:基于localhost 无法联通MySQL 服务器,提示错写信息为:
wz2012@LAPTOP-8R0KHL88:/mnt/e/ubuntu_code$ ./mysql_demo
Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (13)
解决办法:将localhost 修改为127.0.0.1
2、问题2:针对问题1,将windows 访问地址由localhost 修改 为127.0.0.1 ,提示的错误信息为:
wz2012@LAPTOP-8R0KHL88:/mnt/e/ubuntu_code$ ./mysql_demo
Can't connect to MySQL server on '127.0.0.1:3306' (111)
解决办法:将localhost 修改为本机IP地址(在window 系统上使用ipconf命令查看本机IP地址)
3、问题3:针对问题2,将mysql 访问地址由127.0.0.1 修改为192.168.43.1, 提升的错误信息为:
wz2012@LAPTOP-8R0KHL88:/mnt/e/ubuntu_code$ ./mysql_demo
Access denied for user 'root'@'LAPTOP-8R0KHL88' (using password: YES)
4、针对问题3 主要是由于MySQL 服务访问权限设置问题造成。
在MySQL 控制台执行如下命令:
use mysql;update user set Host='%' where User ='root';FLUSH PRIVILEGES;
第五步: 基于MySQL 联通代码,打印指定数据库所有表名:
#include <mysql/mysql.h>
#include <stdio.h>
// MySQL 数据库连接
int main(void){// 数据库连接MYSQL *conn;// 数据库集合MYSQL_RES *res;// 数据库行记录MYSQL_ROW row;char *server = "192.168.43.1";char *user = "root";char *password = "123456"; /* 此处改成你的密码 */char *database = "base";/*数据库,比如base*/conn = mysql_init(NULL);/* 数据库连接 */if (!mysql_real_connect(conn, server,user, password, database, 0, NULL, 0)) {fprintf(stderr, "%s\n", mysql_error(conn));exit(1);}/*SQL 查询 */if (mysql_query(conn, "show tables")) {fprintf(stderr, "%s\n", mysql_error(conn));exit(1);}res = mysql_use_result(conn);/* 输出表名 */printf("MySQL Tables in mysql database:\n");while ((row = mysql_fetch_row(res)) != NULL)printf("%s \n", row[0]);/* 关闭数据库连接 */mysql_free_result(res);mysql_close(conn);return 0;}
结果输出:
wz2012@LAPTOP-8R0KHL88:/mnt/e/ubuntu_code$ ./mysql_demo
MySQL Tables in mysql database:
base_user
bds_building
bds_building_progress
bds_contract
bds_contract_entity
bds_contract_house
bds_enterprise_org
bds_house
bds_house_flag
bds_license
bds_license_house
bds_project
bds_subs_contract
bds_subs_contract_entity
bds_subs_contract_house
bds_yw_wqba
gethouse
第六步: 基于MySQL 基础代码,封装通用表增删改查操作。
待补充