PHP 7 Data Structures and Algorithms

Building an N-level category tree using recursion

Building a multilevel nested category tree or menu is always a problem. Many CMS and sites only allow a certain level of nesting. In order to save performance issues due to multiple joins, some only allow 3-4 levels of nesting at maximum. Now, we will explore how we can create an N-level nested category tree or menu with the help of recursion, without compromising on performance. Here is our approach for the solution:

1. We will define the table structure for the category in the database.
2. We will get all categories in the table without the use of any join or multiple queries. It will be a single database query with a simple select statement.
3. We will build an array of categories such that we ...