如何使亲子关系正常工作？

Question

I am building a website of engineering and construction in which I have list of products such as bridge, towers and all are linked. When the user clicks on bridge then its type appears from mysql table on the same page which is in the form of image but the problem is again I want to retrieve the value ie its sub-types which are also images. And then when user clicks that image its details will be appeared. Basically its a hierarchy up to 3-4 levels. But don't know how to make relationships between tables.

Answer 1

If the items in your hierarchy can be generalized enough, you could make a single table with the columns: id, parent, information

One entry could be id=Bridge, Parent=Architecture, information=picture_source

You can then make lookups like, show me every entry that has Architecture as its parent and send the list to the client.

Answer 2

Use InnoDB engine for mysql. MyISAM don't support foreign keys (if you are using the default).

you can use:

ALTER TABLE table_name ENGINE=InnoDB;

Answer 3

use parent -child relationships like this,
example:

1. when clicked on bridge - take data from child 1 table having same fk-key from main table , so your all bridge types will appear
2. Do same for all your sub items