Manage Minimum And Maximum Values In 'attributes And Values':

[rcondor]

Hello
I have a problem to solve: add and manage minimum and maximum values in 'Attributes and Values':
I need to add fields min_val and max_val to compare them when choosing, in the product, an attribute line (see picture attached MinMax BO.png)
Eg. In the attributes of a product there are three values:
00-05 mt = 10,00 €
06-11 mt = € 8.00
12-24 mt = 6,00 €
To prevent the client to put 4 mt in the 3rd row (12-24 mt = 6,00 €) and buy the product at 6,00 €, I will have to compare the minimum and maximum values ​​specified in the screen side BO.
I do not know which files they read and save data attributes and values ​​side BO.
I tried to adjust the values ​​in MySQL, but not read them (and does not change)
Of course I know that the structure attribs is divided into 3 parts and I am considering only ps_layered_indexable_attribute_lang_value:

Could someone give me a tip and said at least WHAT are the files where saves and reads the record _attribute?
Thank you in advance
Roberto