Where to store constants?

Question

Magento

In magento 2, the module has scripts for installing schemas and data. One of the tables has special identifiers that will be used later. There was a desire to use constants, but where to put it is not clear.
It is impossible in the model, because it will be strange to connect the model for tables that do not yet exist. Maybe you need to use helper. What do you say?

Answer 1

Helpers