PHP Advanced: Implementing Unlimited Categories Page 1/4
1. Analysis
When we use php to make a website, classification is very important. Under the classification, the second category is called a sub-category. However, most websites are now only classified into the third category:
First Classification (parent classification)-->Second classification (child classification)-->Third classification (grandchild classification)
The more such related classifications, the more complicated and difficult it is to control the program and database. At the same level Classification processing and control are very simple, because only a 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 It is not enough to say that one-level classification is needed, and further classification is needed, such as:
System-->linux, windows
News-->linux news, windows news
This classification will be clearer, at least people can understand, system Including linux and windows, and the news includes linux news and windows news. In order to make the information more clear, we continue to classify:
linux-->system tools, kernel, programming language, development tools
...
The classification has reached the third At the third level, the processing of information materials becomes clearer. That is to say, in order to process the information clearly, the more detailed the classification, the more convenient it is. This not only facilitates the processing of information, but also makes it easier for netizens to find the information they need with a clear purpose. But as time goes on, The detailed classification 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 problem It 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 first-level classification to build a database when processing databases. As for the database approach, I also adopted this method to handle classification at the time. Since most websites are classified into the third level, there are only three classification databases in the database for processing. But when it is necessary to continue to classify downwards, this approach The disadvantages 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 establish an infinite downward classification classification method, using windows All readers know that the Windows folder can create unlimited hierarchical directories, and you can continue to create directories under the directories, so that they can be divided endlessly. Linux directory creation also has this function. The method I introduced is the same as this form. .
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