Common commands for PHP database operations

<?<span>php
</span><span>//</span><span>设置字符集</span><span>header</span>("content-type:text/html;charset=utf8"<span>);
</span><span>//</span><span><strong>连接数据库</strong>并判断成功与否</span><span>$link</span>=<span>mysql_connect</span>('localhost','root','root')or <span>die</span> ('连接失败'<span>);
</span><span>//</span><span>选择数据库</span><span>mysql_select_db</span>('数据库名'<span>);
</span><span>//</span><span>设置字符集</span>mysql_set_charset('utf8'<span>);
</span><span>//</span><span>准备sql语句</span><span>$sql</span>="select * from user"<span>;
</span><span>//</span><span>发送sql语句</span><span>$result</span>=<span>mysql_query</span>(<span>$sql</span><span>);
</span><span>//</span><span>判断执行的sql语句是否成功</span><span>if</span>(<span>$result</span> && <span>mysql_affected_rows</span>()>0<span>){
    </span><span>echo</span> '查询成功'<span>;
}</span><span>else</span><span>{
    </span><span>echo</span> '查询失败'<span>;
}
</span><span>//</span><span>关闭数据库连接</span><span>mysql_close</span><span>();

</span><span>//</span><span>PHP数据库操作常用命令</span><span><strong>require</strong></span> ,<span>include</span><span>//</span><span>使用 函数将某个文件包含进来</span><span>mysql_connect</span>('localhost','root','root')<span>//</span><span><strong>连接数据库</strong></span><span>mysql_select_db</span>('数据库名')<span>//</span><span>选择数据库</span>mysql_set_charset('utf8')<span>//</span><span>设置字符集</span><span>mysql_errno</span>()<span>//</span><span>错误号</span><span>mysql_error</span>()<span>//</span><span>错误信息</span><span>mysql_query</span>('sql语句')<span>//</span><span>执行sql语句成功返回资源,失败返回false</span><span>mysql_free_result</span>(<span>$result</span>)<span>//</span><span>释放资源</span><span>mysql_close</span>()<span>//</span><span>关闭数据库</span><span>mysql_affected_rows</span>(<span>$link</span>)<span>//</span><span>返回受影响行数 一般 添加 修改 删除的时候进行判断</span><span>mysql_insert_id</span>(<span>$link</span>)<span>//</span><span>如果表中有自增id 添加成功将通过此函数返回自增id</span><span>mysql_num_rows</span>(<span>$result</span>)<span>//</span><span>只用于查询 返回结果集中的记录数</span><span>mysql_fetch_array</span>(<span>$result</span>)<span>//</span><span>将结果集中的记录以数组的形式返回 混合数组 了解即可</span><span>mysql_fetch_row</span>(<span>$result</span>)<span>//</span><span>将结果集中的记录以数组的形式返回 <strong>索引</strong>数组 了解即可</span><span>mysql_fetch_assoc</span>(<span>$result</span>)<span>//</span><span>将结果集中的记录以数组的形式返回 关联数组  推荐使用并且掌握</span>

The above introduces the common commands for PHP database operations, including require, index, and database connection. I hope it will be helpful to friends who are interested in PHP tutorials.