Database link between orders

Wich table that links sales order to sales invoice in my erpnext database

It’s a good question @Elie, I’m not sure but the when you create a field and if the fieldtype of this field is “Link” you create a ‘connection’ something like a FK, in the table ‘tabDocField’ you can find your field, the column ‘parent’ is where your field was created and the column ‘Option’ is the Doctype of the field.

this isn’t my question i mean the sales invoice that i make my sales order from it this table i mean @Thiago_Henry