PHP infinite classification program code_PHP tutorial-PHP Tutorial-php.cn

Infinite classification is mostly used when classifying data. For example, our news or software channels may have various subcategories, but we don’t know these subcategories, so we have to use the infinite classification method. Let me introduce it to you.

First category (parent category)–>Second category (child category)–>Third category (grandchild category)

The more such kinship classifications, the more complicated and difficult it is to control the program and database. Classification processing and control at the same level is very simple, because only one database is needed to record this level of classification. , such as: system, news and other classifications, processing at this level is very simple, but for a website, the first-level classification is not enough, and it needs to be classified again, such as:

System–>linux,windows
News–>linux news,windows news

This classification will be clearer, at least it will make people understand that the system includes linux and windows, and the news includes linux news and windows news. In order to make the information clearer, I will continue to classify:

linux–>System tools, kernel, programming languages, development tools
…

When the classification reaches the third level, the processing of information becomes clearer. In other words, in order to process the information clearly, the more detailed the classification, the more convenient it is. This makes it easier to process information and make it easier for netizens to find what they need with a clear purpose. Data, but as the classification continues to be refined, it will become more and more difficult to control the program and database.

Difficulty 1: How to deal with these related kinship classifications in the database?
Difficulty 2: How to use php to complete this clear relationship?

This kind of multi-level and detailed classification is a problem that every PHP programmer must solve, because the classification problem of making a good and excellent website is inevitable, and solving this problem is quite complicated, among which the biggest The biggest problem is the classification processing of the database, because if the database is not handled properly, it will bring a huge workload and even have to re-plan the database...

This is not an exaggeration, because many people will use the first-level classification to build a database when processing databases. I also adopted this method to handle classification at that time, because most websites are classified into the third level, so There are only three classification databases in the database for processing. But when it is necessary to continue to classify downwards, the disadvantages of this approach are revealed, because the further down the classification, the workload and program volume will increase dramatically..

The method I want to introduce is how to use a classification database to create an infinite downward classification method. Readers who have used Windows all know that the windows folder can create an unlimited downward classification directory, and you can continue to create directories below the directory. , divided endlessly, Linux directory creation also has this function, the method I introduced is the same as this form.

Database planning
We talked about the complexity of classification earlier, so how to plan the database has become a very important step to achieve unlimited classification.

I once introduced the database planning of the forum. Yes, the forum can achieve unlimited follow-up. Unlimited classification is an extension of this form. Classification also has this kind of child-father relationship, so the classification database is how to establish and clearly define this There are several difficulties in the seed-parent relationship.

1) How to handle information storage of each category;
2) How to deal with the kinship relationship of classification;
3) How to handle inquiries for information;

The database processing of kinship relationships is similar to the database processing of forums. Here we build a type database to handle classification:

Create fields:
id(int): used to record the natural serial number of each category
uid(int): used to record the id number of the parent category of this category
type(char): name of category
roue_id (varchar): kinship tree, connecting with the id of :0:2:10:20: to indicate the kinship relationship
roue_char (varchar): Affinity tree, similar to: system: linux: development tools: gcc: (It doesn’t matter whether this field is present or not. In order to understand each affinity more conveniently, of course character expression is more direct than numerical expression ^o^, but it is best Add this field)

Such an unlimited category table has been established. Next, you need to establish a database to store information. It is most convenient to process and query a table, so here is a table to store information type_message:

id(int): the serial number of the message;
typeid(int): ID number of the category;
title(varchar): information title;
message(text): message content;
time: the time when the information was created;

These two data tables can complete the task of infinite classification (the auxiliary fields of the two tables are not added, readers can add them by themselves).

The rest of the tasks will be handled by php.

Program control
This step is the most complicated and laborious to implement the infinite classification function. First, let’s take a look at the steps that the program needs to complete:

1) Create categories for upload;
2) Create information to upload;
3) Clearly display each category and the relationship between them;
4) Query processing function;
5) How to handle the editing and deletion functions;

The most difficult of these five steps is the fifth step, because editing and deleting categories involves uniformity issues.

I will describe the program control of php one by one below:

1) Create categories and upload

Before introducing this function, let’s first introduce the explode() function. This is a string processing function used to decompose strings. The specific usage is as follows:

Decompose the numbers in "0:1:2:3:4"

$val="0:1:2:3:4";
$rid=explode(":",$val);

After being processed by the explode() function, all the numbers in $val are decomposed into the $rid array. When you want to quote, just print: echo “$rid[0],$rid[1],$rid[2 ]…”; That’s it. The explode( ) function plays a very important role in the entire classification process. Now let’s introduce the program control of non-current classification.

You can assume that there is a total classification of 0, and all categories are its descendants. Now let’s establish the first classification “system” and see how it is stored in the database:

id | uid | type | rout_id | rout_char
1 | 0 | System | 0:1 | System

Then divide "Linux" below:

id | uid | type | rout_id | rout_char
2 | 1 | Linux| 0:1:2 | SystemLinux

The above is the form of database storage. Now let’s complete the php code. This is very similar to the forum code. All we have to do is put the category id into uid, and the parent category’s uid into 0. Next Take a look at the code:

The code is as follows

Copy code

.....
.....

//Set the default page
if (empty($func)) $func=="showtype";

//Set the uid of the parent category
if (empty($uid)) $uid=0;

//Database storage************************************************ *****
if ($func=="save"):

$fields = "";
$values = "";

if ($id!="") {
$fields .= ",id";
$values.=",$id";
}

if ($uid!="") {
$fields .= ",uid";
$values.=",$uid";
}

if ($type!="") {
$fields .= ",type";
$values.=","$type"";
}

if ($route_id=="") {

//Get the route_id of the parent category
if ($uid!=0) {
$result = mysqlquery("select * from type where id=$uid");
$route_id=mysql_result($result,0,"route_id");
} else {
$routr_id="0";
}
$fields .= ",route_id";
//Form your own route_id
$route_id="$route_id:$id";
$values.=","$route_id"";
}

//Form your own route_char
if ($route_char!="") {
$fields .= ",route_char";
$route_char="$route_char:$type";
$values.=","$route_char"";
} else {
$fields .= ",route_char";
$route_char=$type;
$values.=","$route_char"";
}

$fields = substr($fields,1,strlen($fields)-1);
$values = substr($values,1,strlen($values)-1);

$result = mysqlquery("insert into type ($fields) values ($values)");
...
endif; /* end save */

//Category upload************************************************ *****
if ($func=="createtype"):

//Get your own id
$result = mysqlquery("select * from type order by
id desc");
$num=mysql_numrows($result);
if (!empty($num)) {
$cat = mysql_result($result,0,"id");
} else {
$cat=0;
}

//Determine the status of the classification
if ($uid != 0) {
$result=mysql_query("select * from type where id=$uid");
$type=mysql_result($result,0,"type");
$route_char=mysql_result($result,0,"route_char");
} else {
$type="parent category";
}
echo "

";
endif; /* end createtype */

//显示分类************************************************
if ($func=="showtype"):

echo "

//判断分类的状态
if ($uid!=0) {
$result=mysql_query("select * from type where id=$uid");
$type=mysql_result($result,0,"type");
} else {
$type="父分类";
}

echo "

$result=mysql_query("select * from type where uid=$uid");
$num=mysql_numrows($result);

if (!empty($num)) {
for ($i=0;$i<$num;$i++) {

$id=mysql_result($result,$i,"id");
$type=mysql_result($result,$i,"type");

echo "

";
}
}

echo "

创建分类

$type

";
echo "$type";
echo "

";
endif; /* end showtype */
.....
.....

以上的程序便完成了无限分类的基本创建,存储和显示,接着就是完善分类创建功能的各个部分了.

路径跟踪
前面已经介绍过了分类的创建实现方法,在分类表里记载了 rout_id 和 rout_char 这两个存储分类路径的信息,在不做任何处理的情况下,程序只能够顺序下到最底层的分类而无法倒退(当然可利用浏览器的 back 键倒退,但这对程序来说是不完整的),因此必须将 rout_id 和 rout_char 的信息分解出来完成实在的路径指示.

具体的做法,假如数据库记载了这么一条分类信息:

id:4
uid:2
type:开发工具
rout_id:0:1:2:4
rout_char:系统:linux:开发工具

当程序走到分类’开发工具’上时,除了要求显示路径信息外还要求能够去到路径上的任一分类中,该怎么做能?这里就需要用到 explode() 函数了.因为 rout_id 和 rout_char 是对应关系的,所以可将它们分解:

代码如下

复制代码

$path=explode(":",$rout_id);
$path_gb=explode(":",$rout_char);

复制代码

$path=explode(":",$rout_id);

$path_gb=explode(":",$rout_char);

代码如下

复制代码

for ($i=0;;$i++) {
$a=$i+1;
echo " href=$php_self?func=showtype&uid=",$path[$a],">",$path_gb[$i],":";
if (empty($path_gb[$i])) {
break;
}
}

这时所有分类信息都被分解了,现在要做的就是以链接的方式还原路径信息:

代码如下

复制代码

for ($i=0;;$i++) { $a=$i+1; echo " href=$php_self?func=showtype&uid=",$path[$a],">",$path_gb[$i],":"; if (empty($path_gb[$i])) { break; } }

The above code implements the function of adding links to restore paths. Because it implements infinite classification, there is no upper limit, so there is no range limit in for($i=0;;$i++), and the loop exit is set. The condition is that the value in $path_gb[$i] is empty. Just insert this code into the program block of the category display layout:

The code is as follows

代码如下

复制代码

.....
.....
//显示分类************************************************
if ($func=='showtype'):

echo "

//判断分类的状态
if ($uid!=0) {
$result=mysql_query("select * from type where id=$uid");
$type=mysql_result($result,0,"type");

//******** 新加入的代码 ***************
$rout_id=mysql_result($result,0,"rout_id");
$rout_char=mysql_result($result,0,"rout_char");
$path=explode(":",$rout_id);
$path_gb=explode(":",$rout_char);
echo "

";
//******** end ***********************

} else {
$type='父分类';
}

echo "

$result=mysql_query("select * from type where uid=$uid");
$num=mysql_numrows($result);

if (!empty($num)) {
for ($i=0;$i<$num;$i++) {

$id=mysql_result($result,$i,"id");
$type=mysql_result($result,$i,"type");

echo "

";
}
}

echo "

";
for ($i=0;;$i++) {
$a=$i+1;
echo " href=$php_self?func=showtype&uid=",$path[$a],">",$path_gb[$i],":";
if (empty($path_gb[$i])) {
break;
}
}
echo "

创建分类

$type