PHP : MySQLi【面向过程】操作数据库【 连接、建库、建表、增、删、改、查、关闭】

<?php/** *数据库操作关键函数 *mysql_connect：连接数据 *mysql_error：最后一次sql动作错误信息 *mysqli_query：执行sql语句，增删该查 *mysql_select_db：选择数据库 *mysql_fetch_array：从查询结果取1条查询记录 *mysql_close：关闭数据库连接 */function println($msg){    echo "<br>";    echo $msg;}/**数据库配置*/$mysql_server_name = "localhost"; //改成自己的mysql数据库服务器$mysql_username = "root"; //改成自己的mysql数据库用户名$mysql_password = ""; //改成自己的mysql数据库密码$mysql_database = "db2"; //改成自己的mysql数据库名$mysql_table = "person"; //改成自己的表名/** * 连接数据库 */$con = mysqli_connect($mysql_server_name, $mysql_username, $mysql_password); //连接数据库if (!$con) {    die('Could not connect: ' . mysqli_error($con));}/** * 删除数据库：db2 */$sql_delete_db = "drop database $mysql_database";if (mysqli_query($con, $sql_delete_db)) {    println("$sql_delete_db ok");} else {    println("$sql_delete_db failed:" . mysqli_error($con));}/** * 创建数据库：db2 */$sql_create_db = "create database $mysql_database";if (mysqli_query($con, $sql_create_db)) {    println("create ok");} else {    println("create failed:" . mysqli_error($con));}/** * 选择数据库；db2 */mysqli_select_db($con, $mysql_database);/** * 创建数据表；person */$sql_create_table = "create table $mysql_table(id int NOT NULL AUTO_INCREMENT,PRIMARY KEY(id),name varchar(15),age int)";if (mysqli_query($con, $sql_create_table)) {    println("create table ok");} else {    println("create table failed:" . mysqli_error($con));}/** * 从表（person）中删除数据； */$sql_delete = "delete from $mysql_table where age = 200";if (mysqli_query($con, $sql_delete)) {    println("delete table ok");} else {    println("delete table failed:" . mysqli_error($con));}/** * 在表（person）中插入新数据； */$age = rand(12, 80);//随机生成年龄$sql_inset = "insert into $mysql_table (name,age) value ('flying_$age',$age)";if (mysqli_query($con, $sql_inset)) {    println("insert table ok");} else {    println("insert table failed:" . mysqli_error($con));}/** * 从表（person）中查询数据； */$sql_select = "select * from  $mysql_table order by age";$result = mysqli_query($con, $sql_select);/**   输出查询结果   */while ($row = mysqli_fetch_array($result)) {    println($row['id'] . " " . $row['name'] . " " . $row['age']);}$result->close();/** * 更新表（person）中数据； */$sql_update = "update $mysql_table set age = 200 where age < 67";$result = mysqli_query($con, $sql_update);println($result);if ($result) {    println("sql_update table ok");} else {    println("sql_update table failed:" . mysqli_error($con));}/** * 关闭数据库连接 */mysqli_close($con);