Trouble with set and update operations

[ashishmacherla]

Hello Katmass77 Team,
I am currently implementing the get,push,update and set operations for my web application, and
encountered the following problems:

1. With push operation I can successfully push the data to the firebase. But, when pushing the data, rather than having a randomkey generated, is there a way to specify my own(customized) key when performing the push operation?
   The call to the operation from my model layer is:
   $this->firebase->push(FirebasePath::BRANDS.$this->brandId.self::CATEGORIES,$allCategories['value']);

where $allCategories is:
array (
'name' => 'brand_categories',
'value' => 'cid1,cid2'
)

2. When performing the set and update operations, instead of updating/setting, the operations is deleting the entire tree from categories till its child (see the image below).
   Note: where 81dc9bdb52d04dc20036dbd8313ed055 is the brandId of every brand we have
   

Can you suggest us if we are implementing in a wrong way or is there a problem with the framework.

[dade80vr]

Following..