We want to send the item’s sales order line ID on every related transaction, such as item fulfilment, invoice, credit, return authorisation. As you know, line ID is not consistent throughout the related records. You can not source line ID in a custom transaction line field and you can not use a workflow for it. Our worst case scenario is to script it. Or is there any better idea?

scripting it is your best case scenario, not worst case.

If it’s our only option, yes, then it’s the best. But pretty bad database structure if you can’t derive an invoice, credit, or RMA line to the original SO line without making shit up by yourself

searches and queries can join to the related line to get the line id

I quite agree with your last statement @Jesper M!

Yes, we can join us back in suiteql from credit to order but prefer not to in this case…