Converting sales order to invoice and linking the transaction

Question

Reposting this to hopefully help someone in the future. Previously it was closed for being "too broad" but the answer turned out to be quite simple. Original question:

I am developing an application that pulls all sales orders entered in the past 24 hours, puts them in a sql database, and then inserts an invoice back into quickbooks for each order. I haven't found much information about how to tie the created invoice to the original sales order though. Is this possible through qbxml/qbfc? I'm using this for code samples and reference, but the links to any information about linking invoices to sales orders are no longer working on there. Most of the information I've found on the subject when searching google or stackoverflow has been for the online version.

EDIT: I'll rephrase the question as I have no idea why this is on hold. Is it possible to establish link from the sales order to the invoice so that the sales order shows as invoiced when accessed in quickbooks. Example:

Answer 1

Withing the qbxml request for adding an invoice, there is an option to include a linked transaction. Including this instead of adding transaction line items will link to the original sales order an import most of the relevant data from it.