Nested Category display in Symfony2 with 4 level - php

Question

I have following table structure store category
When I wiil start to create my form, I have add first dropdown for lvl 1 category by default, now i want to another dropdown for sub-category which based on category, then I want 3rd lvl sub-category which are based on 2nd lvl selected sub-cateogry list.
I have only store 4 levels, Any Idea about how can build this structure on Symfony2.3?
Any Possibility to make above functionality manage in symfony2.3 or need to change in SQL table structure?

Answer 1

If you're using an entity to access your table, this extensions seems to be made for what you're trying to achieve:
https://github.com/Yavin/symfony-form-tree
You might have to modify your table structure slightly, though.

Answer 2

If you're sure you'll never have more than 4 levels, you could have 4 nested foreach cycles and produce an array similar to:
$categories = array("Electronics" =>
array("Television" =>
array("LED" =>
array(7 => "X SERIES",
8 => "TRILUMINOS")
)
)
);
and then pass it into your form like so:
$form = $this->createFormBuilder()
->add('category', 'choice', array(
'choices'=> $choices
))

Answer 3

I would solve it like this:
don't save redundant data or optimize, so remove 'level' and let's solve it for any depth. Limitations are often more complicated and bad code than solving the whole problem. If you don't want more levels, than just check the level when inserting a child, but when designing the model/entity layer, think about 0,1,n relations.
save the parent id as nullable integer foreign key, so a root category is defined by having parent id NULL and a leaf is defined by not being parent to any other category. This 1:n relation means parent id is the owning side, and a pseudo field 'children' (ArrayCollection) is the reversed side, that's doctrine.
The idea:
The form and request data is just the 'current category'. There is only one path from the current selected category to its root, so we don't need more data.
The validation of the form is simply a check: if category is a leaf, than the form is valid.
The model-view transformer takes a category and transforms it into its children. NULL at first is transformed into the root categories (something like CategoryRepository::findRoots()), and any valid category is transformed into its children (e.g. Category::getChildren()). You have to declare your transformer as a service since it depends on the database.
So use 'entity' as form type so we don't need to write our own view transformation. The entity form type is actually a choice form type and takes an array of items, but is now taking a single category and showing its children.
And please don't use any validation logic in the controller. An action like http://symfony.com/doc/current/book/forms.html#handling-form-submissions works for you. Let the isValid method invoke your validators via a constraint like #Leaf in your data object (like this example: http://symfony.com/doc/current/book/forms.html#embedding-a-single-object).
And don't forget
to hide items with status = 0
remember maybe there is a parent with all children having status = 0, so check that there are no children with status != 0 and not just if it's empty
There are so many exception when dealing with forms. I really recommend to write tests (but also for other parts ;) )!