Well, I don’t know whats your situation, but I would suggest you to use register_taxonomy() function to create a taxonomy for your posts or other custom post type. But if you don’t wanna use this default system then there are some other ways to do that also.
Before going to the procedures we must know what actually taxonomies do. They just group some elements or thing together. So if we can group some element together without using register_taxonomy() function then it can be used as a taxonomy for this elements. So now the question is how can we group the elements ? Here comes the procedures part. Sure there are plenty of them, but this time I can suggest you the below ways-
- Use Post Meta: You can use post meta to contain a token which will represent a certain group. The you can query based on that token and this way you can classify the posts per group. In short this post meta will work as a taxonomy.
- Custom Database Tables: You can use two custom database tables to store the terms and the term-object relation. For each term in the terms table a value would be inserted. And in another table the relation between terms and elements or object will be saved. This way you can also have the taxonomy functionality without calling
register_taxonomy().
But remember, usually creating taxonomy functionality using
register_taxonomy()is the best practice and the taxonomies should be created this way.
Hope the above answer help you.