Linux C 操作MySQL

概述

1. MySQL安装时，请确保安装了MySQL-server、MySQL-client、MySQL-devel。

安装过程请参考：​​https://blog.51cto.com/weiyuqingcheng/5753459​​

2. 整理MySQL include目录

# 创建MySQL include目录
mkdir /usr/include/mysql

# 将MySQL include复制到放入创建的文件夹中
cp -r /usr/src/debug/mysql-8.0.30/mysql-8.0.30/include/ /usr/include/mysql

3. 创建MySQL C库软连接

cd /usr/lib64/mysql

ln -s /usr/lib64/mysql/libmysqlclient.so.18.1.0 /usr/lib64/mysql/libmysqlclient.so

4.创建C项目（我是用的QtCreator创建的）

# 引入MySQL include目录
INCLUDEPATH += /usr/include/mysql

# 链接MySQL动态链接库
LIBS += -L/usr/lib64/mysql -lmysqlclient

5. 编写代码

#include <stdio.h>
#include <stdlib.h>
#include <mysql.h>

int main()
{
    MYSQL *pMySql = mysql_init( NULL );
    mysql_real_connect( pMySql, "192.168.232.162", "test", "xxxx", "test", 3306, NULL, 0  );
    if( !pMySql )
    {
        printf( "Connect mysql error: %s\n", mysql_error( pMySql ) );
        return -1;
    }

    //query
    char strSql[] = "select * from TABLE_DESC;";
    int nRet = mysql_real_query( pMySql, strSql, sizeof( strSql ) );
    if( nRet != 0 )
    {
        printf( "Query failed: %s\n", mysql_error( pMySql ) );
        return -1;
    }

    //print result
    MYSQL_RES* pResult = mysql_store_result( pMySql );
    int nRowNum = mysql_num_rows( pResult );
    int nColumnNum = mysql_num_fields( pResult );
    printf( "Row num: %d, Column num: %d\n", nRowNum, nColumnNum );

    MYSQL_ROW rowData;
    while( ( rowData = mysql_fetch_row( pResult ) ))
    {
        for( int n = 0; n < nColumnNum; n++ )
        {
            printf( "%s\t", rowData[ n ] );
        }
        printf( "\n" );
    }

    mysql_free_result( pResult );
    mysql_close( pMySql );

    return 0;
}

遇到的问题

• 问题：测试代码时，运行到 mysql_real_query() 函数时，报错：mysql server has gone away。
• 原因：未安装 mysql-community-devel-8.0.30-1.el7.x86_64.rpm