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 (!$selectedDb) { die("could not to the databasen" . mysql_error());}$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 databasen" . 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: 24 111
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, $database);// 编码转化为 utf8if (!$mysqli->set_charset("utf8")) { printf("Error loading character set utf8: %sn", $mysqli->error);} else { printf("Current character set: %sn", $mysqli->character_set_name());}if (mysqli_connect_errno()) { // 诊断连接错误 die("could not connect to the database.n" . mysqli_connect_error());}$selectedDb = $mysqli->select_db($database);//选择数据库if (!$selectedDb) { die("could not to the databasen" . mysql_error());}if ($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。