php可以通过三种方式操作数据库，分别用mysql扩展库，mysqli扩展库，和mysqli的预处理模式分别举案例加以说明
1.通过mysql方式操作数据库
工具类核心代码：
<?php
class SqlTool{
private $conn = null;
private $host = "localhost";
private $username = "root";
private $password = "254416";
function __construct(){
$this->conn = mysql_connect($this->host,$this->username,$this->password);
if(!$this->conn){
die("数据库链接失败".mysql_error());
}
//选择数据库
mysql_select_db("test") or die("数据库不存在".mysql_error()) ;
//设置编码
mysql_set_charset ( "utf8",$this->conn);
//mysql_query("set names utf8");
}
function execute_dql($sql){
$res = mysql_query($sql,$this->conn);
if(!$res){
die("数据查询失败");
}else{
return $res;
}
}
function execute_dml($sql){
$res = mysql_query($sql,$this->conn);
if(!$res){
echo mysql_error();
return -1;
}else{
if(mysql_affected_rows($this->conn)>0){
return 1;
}else{
return 0;
}
}
}
} ?>
2.通过mysqli扩展库操作mysql
工具类核心代码：
<?php
class SqlTool{
private $host = "localhost";
private $username = "root";
private $password = "254416";
private $db = "test";
private static $mysqli = null;
function __construct(){
//新建链接
self::$mysqli = new MySQLi($this->host,$this->username,$this->password,$this->db);
if(self::$mysqli->connect_error){
die("数据库连接失败".self::$mysqli->connect_error);
}
//设置编码
self::$mysqli->set_charset("utf8");
}
function execute_dql($sql){
$res = self::$mysqli->query($sql);
return $res;
}
function queryfiledname($sql){
$filedname = self::$mysqli->query($sql);
return $filedname;
}
function execute_dml($sql){
$b = self::$mysqli->query($sql);
if(!$b){
return -1;
}else{
if(self::$mysqli->affected_rows>0){
return 1;
}else{
return 0;
}
}
}
}
?>
3.mysqli扩展库的预处理方式
处理dml语句：
<?php
header("Content-type: text/html;charset=utf-8");
//建立链接
$mysqli = new MySQLi("localhost","root","254416","test");
$sql = "insert into user (username,password,email,address,age) values (?,?,?,?,?)";
//设置编码
$mysqli->query("SET NAMES utf8");
//数据库预处理
$mysqli_stmt = $mysqli->prepare($sql) or die("数据库预处理失败");
//绑定参数
$name="小倩";
$password = "123";
$email = "[email protected]";
$address = "郑州";
$age = 20;
$mysqli_stmt->bind_param("ssssi",$name,$password,$email,$address,$age) or die("绑定参数失败");
//执行
$b = $mysqli_stmt->execute();
if(!$b){
die("预处理执行失败");
}
echo "添加成功";
$mysqli_stmt->close();
?>
处理dql语句：
<?php
header("Content-type: text/html;charset=utf-8");
$mysqli = new MySQLi("localhost","root","254416","test");
$mysqli->query("set names utf8");
$sql="select * from user where id>?";
$mysqli_stmt = $mysqli->prepare($sql) or die("数据库预处理失败");
$id=20;
$mysqli_stmt->bind_param("i",$id) or die("参数绑定失败");
$mysqli_stmt->bind_result($id,$username,$password,$email,$address,$age) or ("绑定结果集失败");
$b = $mysqli_stmt->execute();
if(!$b){
die("数据库预处操作理失败");
}
while($mysqli_stmt->fetch()){
echo "--$id--$username";
}
$mysqli_stmt->free_result();
$mysqli_stmt->close();
$mysqli->close();
?>