记录一下PHP连接MySQL的三种方式。
先mock一下数据,可以执行一下sql。
/*创建数据库*/ CREATE DATABASE IF NOT EXISTS `test`; /*选择数据库*/ USE `test`; /*创建表*/ CREATE TABLE IF NOT EXISTS `user` ( name varchar(50), age int ); /*插入测试数据*/ INSERT INTO `user` (name, age) VALUES('harry', 20), ('tony', 23), ('harry', 24);
第一种是使用PHP原生的方式去连接数据库。代码如下:
<?php $host = 'localhost'; $database = 'test'; $username = 'root'; $password = 'root'; $selectName = 'harry';//要查找的用户名,一般是用户输入的信息 $insertName = 'testname'; $connection = mysql_connect($host, $username, $password);//连接到数据库 mysql_query("set names 'utf8'");//编码转化 if (!$connection) { die("could not connect to the database.\n" . mysql_error());//诊断连接错误 } $selectedDb = mysql_select_db($database);//选择数据库 if (!$selectedDb) { die("could not to the database\n" . mysql_error()); } $selectName = mysql_real_escape_string($selectName);//防止SQL注入 $query = "select * from user where name = '$selectName'";//构建查询语句 $result = mysql_query($query);//执行查询 if (!$result) { die("could not to the database\n" . mysql_error()); } while ($row = mysql_fetch_row($result)) { //取出结果并显示 $name = $row[0]; $age = $row[1]; echo "Name: $name Age: $age \n"; } //添加记录 $insertName = mysql_real_escape_string($insertName);//防止SQL注入 $insertSql = "insert into user(name, age) values('$insertName', 18)"; $result = mysql_query($insertSql); echo $result . "\n"; //更新记录 $updateSql = "update user set age = 19 where name='$insertName'"; $result = mysql_query($updateSql); echo $result . "\n"; //删除记录 $deleteSql = "delete from user where age = 19"; $result = mysql_query($deleteSql); echo $result . "\n"; mysql_close($connection);//关闭连接
其运行结构如下:
Name: harry Age: 20
Name: harry Age: 24
1
1
1
第二种时使用mysqli扩展去链接数据库,代码如下:
<?php $host = 'localhost'; $database = 'test'; $username = 'root'; $password = 'root'; $selectName = 'harry';//要查找的用户名,一般是用户输入的信息 $insertName = 'testname'; // 创建对象并打开连接,最后一个参数是选择的数据库名称 $mysqli = new mysqli($host, $username, $password, $database); // 编码转化为 utf8 if (!$mysqli->set_charset("utf8")) { printf("Error loading character set utf8: %s\n", $mysqli->error); } else { printf("Current character set: %s\n", $mysqli->character_set_name()); } if (mysqli_connect_errno()) { // 诊断连接错误 die("could not connect to the database.\n" . mysqli_connect_error()); } $selectedDb = $mysqli->select_db($database);//选择数据库 if (!$selectedDb) { die("could not to the database\n" . mysql_error()); } if ($stmt = $mysqli->prepare("select * from user where name = ?")) { /* bind parameters for markers */ $stmt->bind_param("s", $selectName); /* execute query */ $stmt->execute(); /* bind result variables */ $stmt->bind_result($name, $age); /* fetch values */ while ($stmt->fetch()) { echo "Name: $name Age: $age \n"; } /* close statement */ $stmt->close(); } //添加记录 if ($insertStmt = $mysqli->prepare("insert into user(name, age) values(?, 18)")) { /* bind parameters for markers */ $insertStmt->bind_param("s", $insertName); /* execute query */ $insertStmt->execute(); echo $insertStmt->affected_rows . "\n"; /* close statement */ $insertStmt->close(); } //更新记录 if ($updateStmt = $mysqli->prepare("update user set age = 19 where name=?")) { /* bind parameters for markers */ $updateStmt->bind_param("s", $insertName); /* execute query */ $updateStmt->execute(); echo $updateStmt->affected_rows . "\n"; /* close statement */ $updateStmt->close(); } //删除记录 $result = $mysqli->query("delete from user where age = 19"); echo $result . "\n"; $mysqli->close();//关闭连接
其结果与第一种相同。
其实mysqli提供了两种方式链接数据库,一种是面向对象的方式,就是如上的代码,另一种是面向过程的方式。可以参考MySQLi扩展功能概述学习。
第三种是使用PDO的方式去连接数据库,代码如下:
<?php $host = 'localhost'; $database = 'test'; $username = 'root'; $password = 'root'; $selectName = 'harry';//要查找的用户名,一般是用户输入的信息 $insertName = 'testname'; $pdo = new PDO("mysql:host=$host;dbname=$database", $username, $password);//创建一个pdo对象 $pdo->exec("set names 'utf8'"); $sql = "select * from user where name = ?"; $stmt = $pdo->prepare($sql); $rs = $stmt->execute(array($selectName)); if ($rs) { // PDO::FETCH_ASSOC 关联数组形式 // PDO::FETCH_NUM 数字索引数组形式 while ($row = $stmt->fetch(PDO::FETCH_ASSOC)) { $name = $row['name']; $age = $row['age']; echo "Name: $name Age: $age \n"; } } $oldAge = 18; $insert = $pdo->prepare('insert into user(name, age) values(:name, :age)'); $insert->bindParam(':name', $insertName, PDO::PARAM_STR); $insert->bindParam(':age', $oldAge, PDO::PARAM_INT); $result = $insert->execute(); echo $result . "\n"; $newAge = 19; $update = $pdo->prepare('update user set age = ? where name = ?'); $update->bindParam(1, $newAge, PDO::PARAM_INT); $update->bindParam(2, $insertName, PDO::PARAM_STR); $result = $update->execute(); echo $result . "\n"; $delete = $pdo->prepare('delete from user where age = ?'); $result = $delete->execute(array($newAge)); echo $result . "\n"; $pdo = null;//关闭连接
其结果与第一种相同。