沉淀再出发:PHP的中级内容
沉淀再出发:PHP的中级内容
一、前言
前面我们介绍了PHP的简单的语法知识以及相关的用法,接下来我们将PHP+mysql以及PHP+ajax结合起来进行研究。
二、PHP+mysql
首先我们看一段代码:
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Document</title> 6 </head> 7 <body> 8 <?php 9 $con=mysqli_connect("127.0.0.1","root",""); 10 // Check connection 11 if (mysqli_connect_errno()) 12 { 13 echo "Failed to connect to MySQL: " . mysqli_connect_error(); 14 } 15 16 // Create database 17 $sql="CREATE DATABASE zyr_db"; 18 if (mysqli_query($con,$sql)) 19 { 20 echo "Database zyr_db created successfully"; 21 echo '<br>'; 22 mysqli_close($con); 23 } 24 else 25 { 26 echo "Error creating database: " . mysqli_error($con); 27 echo '<br>'; 28 } 29 30 $con=mysqli_connect("127.0.0.1","root","","zyr_db"); 31 // Check connection 32 if (mysqli_connect_errno()) 33 { 34 echo "Failed to connect to MySQL: " . mysqli_connect_error(); 35 echo '<br>'; 36 } 37 38 // Create table 39 $sql="CREATE TABLE Persons(FirstName CHAR(30),LastName CHAR(30),Age INT)"; 40 41 // Execute query 42 if (mysqli_query($con,$sql)) 43 { 44 echo "Table persons created successfully"; 45 echo '<br>'; 46 } 47 else 48 { 49 echo "Error creating table: " . mysqli_error($con); 50 echo '<br>'; 51 } 52 53 mysqli_query($con,"INSERT INTO Persons (FirstName, LastName, Age) VALUES ('zyr', 'lsx',24)"); 54 mysqli_query($con,"INSERT INTO Persons (FirstName, LastName, Age) VALUES ('xiaohong', 'xiaoming',30)"); 55 echo "after INSERT..."; 56 echo "<br>"; 57 findAllPeoples($con); 58 59 echo "find by firstname ..."; 60 echo "<br>"; 61 findPeopleById("zyr",$con); 62 63 mysqli_query($con,"UPDATE Persons SET Age=25 WHERE FirstName='zyr' AND LastName='lsx'"); 64 echo "after UPDATE..."; 65 echo "<br>"; 66 findAllPeoples($con); 67 68 mysqli_query($con,"DELETE FROM Persons"); 69 echo "after delete..."; 70 echo "<br>"; 71 findAllPeoples($con); 72 mysqli_close($con); 73 74 function findPeopleById($name,$con){ 75 $result = mysqli_query($con,"SELECT * FROM Persons WHERE FirstName = ". "'" .$name."'"); 76 77 while($row = mysqli_fetch_array($result)) 78 { 79 echo $row['FirstName'] . " " . $row['LastName'] ." ".$row['Age']; 80 echo "<br>"; 81 } 82 } 83 function findAllPeoples($con){ 84 $result = mysqli_query($con,"SELECT * FROM Persons"); 85 86 while($row = mysqli_fetch_array($result)) 87 { 88 echo $row['FirstName'] . " " . $row['LastName'] ." ".$row['Age']; 89 echo "<br>"; 90 } 91 } 92 ?> 93 94 </body> 95 </html>
在我们安装的wamp中,mysql数据库默认的用户名为root,密码为空,因此我们可以连接数据库了,除此之外和其它数据库一样,mysql的数据库操作方法,想必大家都是了如指掌的,并且在PHP之中对于所有的sql操作都做了封装,我们只需要修改或者组合简单的sql语句就能够进行创建、删除数据库、表,以及增删改查表中的内容了,到了这一步,我们可以进行简单的封装使得我们的sql语言更加的精致。
2.1、创建数据库
1 $con=mysqli_connect("127.0.0.1","root",""); 2 // Check connection 3 if (mysqli_connect_errno()) 4 { 5 echo "Failed to connect to MySQL: " . mysqli_connect_error(); 6 } 7 8 // Create database 9 $sql="CREATE DATABASE zyr_db"; 10 if (mysqli_query($con,$sql)) 11 { 12 echo "Database zyr_db created successfully"; 13 echo '<br>'; 14 mysqli_close($con); 15 } 16 else 17 { 18 echo "Error creating database: " . mysqli_error($con); 19 echo '<br>'; 20 }
2.2、创建表
1 $con=mysqli_connect("127.0.0.1","root","","zyr_db"); 2 // Check connection 3 if (mysqli_connect_errno()) 4 { 5 echo "Failed to connect to MySQL: " . mysqli_connect_error(); 6 echo '<br>'; 7 } 8 9 // Create table 10 $sql="CREATE TABLE Persons(FirstName CHAR(30),LastName CHAR(30),Age INT)"; 11 12 // Execute query 13 if (mysqli_query($con,$sql)) 14 { 15 echo "Table persons created successfully"; 16 echo '<br>'; 17 } 18 else 19 { 20 echo "Error creating table: " . mysqli_error($con); 21 echo '<br>'; 22 }
2.3、插入数据
1 mysqli_query($con,"INSERT INTO Persons (FirstName, LastName, Age) VALUES ('zyr', 'lsx',24)"); 2 mysqli_query($con,"INSERT INTO Persons (FirstName, LastName, Age) VALUES ('xiaohong', 'xiaoming',30)"); 3 echo "after INSERT..."; 4 echo "<br>"; 5 findAllPeoples($con);
2.4、查找所有数据
1 function findAllPeoples($con){ 2 $result = mysqli_query($con,"SELECT * FROM Persons"); 3 4 while($row = mysqli_fetch_array($result)) 5 { 6 echo $row['FirstName'] . " " . $row['LastName'] ." ".$row['Age']; 7 echo "<br>"; 8 } 9 }
2.5、按条件查找数据
1 echo "find by firstname ..."; 2 echo "<br>"; 3 findPeopleById("zyr",$con);
其中findPeopleById("zyr",$con);为:
1 function findPeopleById($name,$con){ 2 $result = mysqli_query($con,"SELECT * FROM Persons WHERE FirstName = ". "'" .$name."'"); 3 4 while($row = mysqli_fetch_array($result)) 5 { 6 echo $row['FirstName'] . " " . $row['LastName'] ." ".$row['Age']; 7 echo "<br>"; 8 } 9 }
2.6、更新数据
1 mysqli_query($con,"UPDATE Persons SET Age=25 WHERE FirstName='zyr' AND LastName='lsx'"); 2 echo "after UPDATE..."; 3 echo "<br>"; 4 findAllPeoples($con);
2.7、删除数据并且关闭数据库
1 mysqli_query($con,"DELETE FROM Persons"); 2 echo "after delete..."; 3 echo "<br>"; 4 findAllPeoples($con); 5 mysqli_close($con);
2.8、删除数据库
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Document</title> 6 </head> 7 <body> 8 <?php 9 $con=mysqli_connect("127.0.0.1","root",""); 10 // Check connection 11 if (mysqli_connect_errno()) 12 { 13 echo "Failed to connect to MySQL: " . mysqli_connect_error(); 14 } 15 16 // Create database 17 $sql="drop DATABASE my_db"; 18 if (mysqli_query($con,$sql)) 19 { 20 echo "Database zyr_db dropped successfully"; 21 mysqli_close($con); 22 } 23 else 24 { 25 echo "Error creating database: " . mysqli_error($con); 26 } 27 ?> 28 </body> 29 </html>
以上就是数据库相关的操作,使用函数进行相应的封装即可。
2.9、php和mysql的对应api
当考虑连接到MySQL数据库服务器的时候,有三种主要的API可供选择: PHP的MySQL扩展 PHP的mysqli扩展 PHP数据对象(PDO) PHP的MySQL扩展: 这是设计开发允许PHP应用与MySQL数据库交互的早期扩展。mysql扩展提供了一个面向过程的接口,并且是针对MySQL4.1.3或更早版本设计的。
因此,这个扩展虽然可以与MySQL4.1.3或更新的数据库服务端进行交互,但并不支持后期MySQL服务端提供的一些特性。 PHP的mysqli扩展: mysqli扩展,称之为MySQL增强扩展,可以用于使用 MySQL4.1.3或更新版本中新的高级特性。mysqli扩展在PHP 5及以后版本中包含。
mysqli扩展有一系列的优势,相对于mysql扩展的提升主要有: 面向对象接口 prepared语句支持 多语句执行支持 事务支持 增强的调试能力 嵌入式服务支持 在提供了面向对象接口的同时也提供了一个面向过程的接口。 PDO: PHP数据对象,是PHP应用中的一个数据库抽象层规范。PDO提供了一个统一的API接口可以使得你的PHP应用不去关心具体要连接的数据库服务器系统类型。
也就是说,如果使用PDO的API,可以在任何需要的时候无缝切换数据库服务器,比如从Firebird 到MySQL,仅仅需要修改很少的PHP代码。
其他数据库抽象层的例子包括Java应用中的JDBC以及Perl中的DBI。当然,PDO也有它自己的先进性,比如一个干净的,简单的,可移植的API,
它最主要的缺点是会限制让你不能使用后期MySQL服务端提供所有的数据库高级特性。比如,PDO不允许使用MySQL支持的多语句执行。
最后我们思考一下,如何在wamp中的mysql之中批量执行sql查询语句呢,这里我们就需要用到mysql的命令行工具了,打开wamp服务器,找到服务器中mysql的按钮,点击之后,选择打开命令行工具,密码默认为空,然后我们创建数据库,并进入数据库之中,之后我们使用source命令来批量执行相应的sql语句。
更多的关于PHP的mysql接口可以从PHP的官方文档:http://php.net/manual/zh/set.mysqlinfo.php上面获取。
三、PHP和ajax
在PHP中使用ajax,我们可以非常方便的进行相应的查询和相应,速度非常的快,这对于我们的动态网页来说是非常方便的。
3.1、数据查询并显示
首先让我们看一下客户端代码:
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Document</title> 6 <script> 7 function showHint(str) 8 { 9 if (str.length==0) 10 { 11 document.getElementById("txtHint").innerHTML=""; 12 return; 13 } 14 if (window.XMLHttpRequest) 15 {// code for IE7+, Firefox, Chrome, Opera, Safari 16 xmlhttp=new XMLHttpRequest(); 17 } 18 else 19 {// code for IE6, IE5 20 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); 21 } 22 xmlhttp.onreadystatechange=function(){ 23 if (xmlhttp.readyState==4 && xmlhttp.status==200) 24 { 25 document.getElementById("txtHint").innerHTML=xmlhttp.responseText; 26 } 27 } 28 xmlhttp.open("GET","gethint.php?q="+str,true); 29 xmlhttp.send(); 30 } 31 </script> 32 </head> 33 34 <body> 35 36 <p><b>在输入框中输入一个姓名:</b></p> 37 <form> 38 姓名: <input type="text" onkeyup="showHint(this.value)"> 39 </form> 40 <p>返回值: <span id="txtHint"></span></p> 41 42 </body> 43 44 </html>
然后是PHP服务器的代码(gethint.php):
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Document</title> 6 </head> 7 <body> 8 <?php 9 // 将姓名填充到数组中 10 $a[]="Anna"; 11 $a[]="Brittany"; 12 $a[]="Cinderella"; 13 $a[]="Diana"; 14 $a[]="Eva"; 15 $a[]="Fiona"; 16 $a[]="Gunda"; 17 $a[]="Hege"; 18 $a[]="Inga"; 19 $a[]="Johanna"; 20 $a[]="Kitty"; 21 $a[]="Linda"; 22 $a[]="Nina"; 23 $a[]="Ophelia"; 24 $a[]="Petunia"; 25 $a[]="Amanda"; 26 $a[]="Raquel"; 27 $a[]="Cindy"; 28 $a[]="Doris"; 29 $a[]="Eve"; 30 $a[]="Evita"; 31 $a[]="Sunniva"; 32 $a[]="Tove"; 33 $a[]="Unni"; 34 $a[]="Violet"; 35 $a[]="Liza"; 36 $a[]="Elizabeth"; 37 $a[]="Ellen"; 38 $a[]="Wenche"; 39 $a[]="Vicky"; 40 41 //从请求URL地址中获取 q 参数 42 $q=$_GET["q"]; 43 44 //查找是否由匹配值, 如果 q>0 45 if (strlen($q) > 0) 46 { 47 $hint=""; 48 for($i=0; $i<count($a); $i++) 49 { 50 if (strtolower($q)==strtolower(substr($a[$i],0,strlen($q)))) 51 { 52 if ($hint=="") 53 { 54 $hint=$a[$i]; 55 } 56 else 57 { 58 $hint=$hint." , ".$a[$i]; 59 } 60 } 61 } 62 } 63 64 // 如果没有匹配值设置输出为 "no suggestion" 65 // or to the correct values 66 if ($hint == "") 67 { 68 $response="no suggestion"; 69 } 70 else 71 { 72 $response=$hint; 73 } 74 75 //输出返回值 76 echo $response; 77 ?> 78 </body> 79 </html>
3.2、网上投票
客户端文件:
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Document</title> 6 <script> 7 function getVote(int) 8 { 9 if (window.XMLHttpRequest) 10 {// code for IE7+, Firefox, Chrome, Opera, Safari 11 xmlhttp=new XMLHttpRequest(); 12 } 13 else 14 {// code for IE6, IE5 15 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); 16 } 17 xmlhttp.onreadystatechange=function(){ 18 if (xmlhttp.readyState==4 && xmlhttp.status==200) 19 { 20 document.getElementById("poll").innerHTML=xmlhttp.responseText; 21 } 22 } 23 xmlhttp.open("GET","poll_vote.php?vote="+int,true); 24 xmlhttp.send(); 25 } 26 </script> 27 </head> 28 <body> 29 <div id="poll"> 30 <h3>Do you like PHP and AJAX so far?</h3> 31 <form> 32 Yes:<input type="radio" name="vote" value="0" onclick="getVote(this.value)"> 33 <br>No: 34 <input type="radio" name="vote" value="1" onclick="getVote(this.value)"> 35 </form> 36 </div> 37 </body> 38 39 </html>
服务器文件(poll_vote.php):
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Document</title> 6 </head> 7 <body> 8 <?php 9 $vote = $_REQUEST['vote']; 10 11 //get content of textfile 12 $filename = "poll_result.txt"; 13 $content = file($filename); 14 15 //put content in array 16 $array = explode("||", $content[0]); 17 $yes = $array[0]; 18 $no = $array[1]; 19 20 if ($vote == 0) 21 { 22 $yes = $yes + 1; 23 } 24 if ($vote == 1) 25 { 26 $no = $no + 1; 27 } 28 29 //insert votes to txt file 30 $insertvote = $yes."||".$no; 31 $fp = fopen($filename,"w"); 32 fputs($fp,$insertvote); 33 fclose($fp); 34 ?> 35 36 <h2>Result:</h2> 37 <table> 38 <tr> 39 <td>Yes:</td> 40 <td> 41 <img src="poll.gif" width='<?php echo(100*round($yes/($no+$yes),2)); ?>' height='20'> 42 <?php echo(100*round($yes/($no+$yes),2)); ?>% 43 </td> 44 </tr> 45 <tr> 46 <td>No:</td> 47 <td> 48 <img src="poll.gif" width='<?php echo(100*round($no/($no+$yes),2)); ?>' height='20'> 49 <?php echo(100*round($no/($no+$yes),2)); ?>% 50 </td> 51 </tr> 52 </table> 53 </body> 54 </html>
文件目录:
四、php+ajax+jQuery
前端:
1 <!doctype html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>评论动态加载</title> 6 <style type="text/css"> 7 .comment{ 8 background: #FFF; 9 #border-bottom: red solid; 10 width: 600px; 11 height: 80px; 12 } 13 .comment div img{ 14 width: 80px; 15 height: 80px; 16 } 17 .left{ 18 float: left; 19 width: 80px; 20 height: 80px; 21 background: blue; 22 } 23 .right{ 24 float: right; 25 width: 520px; 26 height: 80px; 27 } 28 #container{ 29 position: relative; 30 left: 50%; 31 width: 600px; 32 margin-left: -300px; 33 } 34 #container ul{ 35 padding-left: 0px; 36 list-style: none; 37 } 38 #more{ 39 background: lightGray; 40 height: 30px; 41 line-height: 30px; 42 text-align: center; 43 cursor: pointer; 44 } 45 #clear{ 46 background: red; 47 height: 30px; 48 line-height: 30px; 49 text-align: center; 50 cursor: pointer; 51 } 52 </style> 53 <script src="http://libs.baidu.com/jquery/1.10.2/jquery.min.js"></script> 54 </head> 55 <body> 56 <div style="height:300px;"></div> 57 <div id="container"> 58 <ul id="contentList"> 59 <li class="comment"> 60 <div class="left"><img src="./g1.jpg"></div> 61 <div class="right"> 62 <div>一篇工作总结</div> 63 <div>我是内容</div> 64 </div> 65 </li> 66 <hr> 67 <li class="comment"> 68 <div class="left"><img src="./g.jpg"></div> 69 <div class="right"> 70 <div>一篇工作总结</div> 71 <div>我是内容2</div> 72 </div> 73 </li> 74 <hr> 75 76 </ul> 77 <div id="more">加载更多...</div> 78 <div id="clear">清零</div> 79 <input type="hidden" id="last" value="0"> 80 </div> 81 82 <script type="text/javascript"> 83 $(function(){ 84 $('#more').click(function(){ 85 var last = $('#last').val(); 86 var url = './data.php?last='+last+'&amount=2'; 87 queryComment(url); 88 }); 89 $('#clear').click(function(){ 90 $('#last').val(0); 91 }); 92 }); 93 94 function queryComment(url){ 95 $.ajax({ 96 type : "get", 97 async: true, 98 url : url, 99 dataType : "json", 100 success : function(data){ 101 if(data == 1){ 102 $('#more').html('没有更多评论!').unbind('click'); 103 return false; 104 } 105 $.each(data,function(i,element){ 106 var nickname = element.nickname; 107 var content = element.content; 108 var time = element.time; 109 var imgpath = element.imgpath; 110 var info = $('<li class="comment"><div class="left"><img src="'+imgpath+'"></div><div class="right"><div>'+nickname+'</div><div></div>'+content+'</div></li><hr>'); 111 $('#contentList').append(info); 112 }); 113 var now = parseInt($('#last').val()) + 2; 114 $('#last').val(now); 115 }, 116 error:function(){ 117 console.log('fail'); 118 } 119 }); 120 } 121 </script> 122 </body> 123 </html>
后端:
1 <?php 2 3 $con=mysqli_connect("127.0.0.1","root","","mydb"); 4 $last = $_GET['last']; 5 $amount = $_GET['amount']; 6 7 $query=mysqli_query($con,"select * from comment order by id desc limit $last,$amount"); 8 $flag = false; 9 while ($row=mysqli_fetch_array($query)) { 10 $flag = true; 11 $sayList[] = array( 12 'id'=>$row['id'], 13 'nickname'=>$row['nickname'], 14 'content'=>$row['content'], 15 'imgpath'=>$row['imgpath'], 16 'time'=>$row['time'] 17 ); 18 } 19 if($flag){ 20 echo json_encode($sayList); 21 }else{ 22 echo true; 23 } 24 25 ?>
sql语句:
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
DROP TABLE IF EXISTS `comment`;
CREATE TABLE `comment` (
`id` int(11) NOT NULL ,
`nickname` varchar(30) DEFAULT NULL,
`content` varchar(30) DEFAULT NULL,
`imgpath` varchar(30) DEFAULT NULL,
`time` datetime DEFAULT NULL,
PRIMARY KEY (`id`)
) ;
-- ----------------------------
-- Records of comment
-- ----------------------------
INSERT INTO `comment` VALUES ('1', '1', '23', './g1.jpg', '2015-12-21 17:59:54');
INSERT INTO `comment` VALUES ('2', '2', '333', './g2.jpg', '2015-12-22 18:00:21');
INSERT INTO `comment` VALUES ('3', 'zhangsan', 'ceshi3', './g3.jpg', '2015-12-21 17:59:54');
INSERT INTO `comment` VALUES ('4', 'zhangsan', 'ceshi4', './g4.jpg', '2015-12-21 17:59:54');
INSERT INTO `comment` VALUES ('5', 'zhangsan', 'ceshi5', './g5.jpg', '2015-12-21 17:59:54');
INSERT INTO `comment` VALUES ('6', 'zhangsan', 'ceshi6', './g0.jpg', '2015-12-21 17:59:54');
INSERT INTO `comment` VALUES ('7', 'zhangsan', 'ceshi7', './g2.jpg', '2015-12-21 17:59:54');
INSERT INTO `comment` VALUES ('8', 'zhangsan', 'ceshi8', './g5.jpg', '2015-12-21 17:59:54');
INSERT INTO `comment` VALUES ('9', 'zhangsan', 'ceshi9', './g.jpg', '2015-12-21 17:59:54');
INSERT INTO `comment` VALUES ('10', 'zhangsan', 'ceshi10', './g2.jpg', '2015-12-21 17:59:54');
INSERT INTO `comment` VALUES ('11', 'zhangsan', 'ceshi11', './g3.jpg', '2015-12-21 17:59:54');
INSERT INTO `comment` VALUES ('12', 'zhangsan', 'ceshi12', './g4.jpg', '2015-12-21 17:59:54');
INSERT INTO `comment` VALUES ('13', 'zhangsan', 'ceshi13', './g5.jpg', '2015-12-21 17:59:54');
运行结果:
五、总结
我们首先学习了在PHP中如何使用mysql数据库,其次我们学习了PHP中使用ajax的相关技巧,通过上面代码和文档的学习,我们已经有了正式使用PHP的能力了,当然PHP中还有很多其他的功能,在这里我们就不一一列举了。