Detailed explanation of the effect of the secondary linkage menu implemented by php mysql, mysql linkage

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Detailed explanation of the effect of the secondary linkage menu implemented by php mysql, mysql linkage_PHP tutorial

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Jul 12, 2016 am 08:52 AM

html codemysqlphp

This article describes the secondary linkage menu effect implemented by php mysql. Share it with everyone for your reference, the details are as follows:

<!--php+mysql二级联动-->
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>生成学院专业级联下拉菜单测试 </title>
</head>
<body>
<&#63; //
/***********************************************
** 功 能： php+mysql+javascript实现学院专业二级级联下拉框
** 数据库：数据库名（ dms）、数据表（ colleges、 majors）
** 表 colleges中字段： college_id（ id编号）、 name（学院名）
** 表 majors中的字段： major_id（ id编号）、 college_id（学院 ID）、 name（学院名）
** version 1.0
** 作 者： wu yaowen
***********************************************/
//****************** 连接选择数据库 ***************
$link = mysql_connect("localhost", "root", "123456")
  or die("Could not connect : " . mysql_error());
mysql_select_db("dms") or die("Could not select database");
//******************提取学院信息 ******************
$queryCol = "select * from colleges order by college_id ";
mysql_query("SET NAMES 'gb2312'");
$result1 = mysql_query($queryCol) or die("Query failed : " . mysql_error());
$colleges = array();
while( $row1 = mysql_fetch_array($result1) )
{
  $colleges[] = $row1;
}
//print_r ($forum_data);
mysql_free_result($result1);
//**************获取专业信息 **************  
$queryMaj = "select * from majors order by college_id desc";
mysql_query("SET NAMES 'gb2312'");
if( !($result2 = mysql_query($queryMaj)) )
{
  die('Could not query t_city list');
}
$majors = array();
while( $row2 = mysql_fetch_array($result2) )
{
  $majors[] = $row2;
}
mysql_free_result($result2);
&#63;>
<!--************ JavaScript处理 college-onChange *************-->
<script language = "JavaScript">
 var majorCount; // 存储专业记录条数
 // form_majors[] 储存专业 major数据，如 {(1,1,电子商务 ),(4,1,计算机科学 ),(3,2,古典文学 )}
 form_majors = new Array();
 <&#63;php
   $num2 = count($majors); // $num2 获取专业表中记录的个数
 &#63;>
   majorCount = <&#63;php echo $num2;&#63;>;
 <&#63;
   for($j=0;$j<$num2;$j++) // 从 0开始取出上面 majors[]中存储的专业数据填充数组
 {
 &#63;>
   form_majors[<&#63;echo $j;&#63;>] = new Array("<&#63;echo $majors[$j]['major_id'];&#63;>","<&#63;echo $majors[$j]['college_id'];&#63;>","<&#63;echo $majors[$j]['name'];&#63;>");
 <&#63;php
 }
 &#63;>
 function changeCollege(college_id)
 {
   document.stu_add_form.major.length = 0;
   var id=id;
   var j;
   document.stu_add_form.major.options[0] = new Option('==选择专业 ==',''); // label的 value为空 ' '
   for (j=0;j < majorCount; j++) // 从 0开始判断
   {
    if (form_majors[j][1] == college_id) // if college_id等于选择的学院的 id
    {
       document.stu_add_form.major.options[document.stu_add_form.major.length] = new Option(form_majors[j][2], form_majors[j][0]);
    }
   }
 }
</script>
<!--********************页面表单 *************************-->
<form name="stu_add_form" method="post">
选择： <select name="college" onChange="changeCollege(document.stu_add_form.college.options[document.stu_add_form.college.selectedIndex].value)" size="1">
<option selected>==请选择学院 ==</option>
<&#63;php
$num = count($colleges);
for($i=0;$i<$num;$i++)
{
&#63;>
<option value="<&#63;echo $colleges[$i]['college_id'];&#63;>"><&#63;echo $colleges[$i]['name'];&#63;></option>
<&#63;
}
&#63;>
</select>
<select name="major">
<option selected value="">==选择专业 ==</option>
</select>
</form>
</body>
</html>

sql statement:

--
-- 表的结构 `colleges`
--
CREATE TABLE IF NOT EXISTS `colleges` (
 `college_id` int(8) NOT NULL auto_increment COMMENT '学院编号自动增加',
 `name` varchar(40) NOT NULL COMMENT '学院名称',
 PRIMARY KEY (`college_id`),
 UNIQUE KEY `name` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=gb2312 AUTO_INCREMENT=7 ;
--
-- 导出表中的数据 `colleges`
--
INSERT INTO `colleges` (`college_id`, `name`) VALUES
(4, '化学与化工学院'),
(1, '计算机与信息科学学院'),
(6, '美术学院'),
(2, '文学院'),
(5, '音乐学院'),
(3, '政治与公共管理学院');
--
-- 表的结构 `majors`
--
CREATE TABLE IF NOT EXISTS `majors` (
 `major_id` int(8) NOT NULL auto_increment COMMENT '专业号，自动增加',
 `name` varchar(40) NOT NULL COMMENT '专业名',
 `college_id` int(8) default NULL COMMENT '所在学院',
 `counsellor_id` int(10) default NULL COMMENT '辅导员',
 PRIMARY KEY (`major_id`),
 UNIQUE KEY `college_id` (`college_id`,`counsellor_id`)
) ENGINE=InnoDB DEFAULT CHARSET=gb2312 AUTO_INCREMENT=8 ;
--
-- 导出表中的数据 `majors`
--
INSERT INTO `majors` (`major_id`, `name`, `college_id`, `counsellor_id`) VALUES
(1, '电子商务', 1, 1),
(2, '音乐视唱', 5, 1),
(3, '古典文学', 2, 1),
(4, '计算机科学', 1, NULL),
(5, '自动化', 1, NULL),
(6, '现代文学', 2, NULL),
(7, '新闻写作', 2, NULL);

Readers who are interested in more PHP-related content can check out the special topics of this site: "Summary of PHP database operation skills based on pdo", "PHP MongoDB database operation skills collection", "php object-oriented programming introductory tutorial", "php Summary of String Usage", "Introduction Tutorial on PHP MySQL Database Operation" and "Summary of PHP Common Database Operation Skills"

I hope this article will be helpful to everyone in PHP programming.

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