This site was built to compliment the existing NetSuite Professionals Slack Community by adding a means for members to easily find answers to common questions and to create a searchable database of those questions and answers.

NetSuite Professionals

Yes, except for JEs where there is no "main line" and 0 is the first line of the JE.

also don't get caught (as I have definitely done) trying to use line ID, b/c when people come in and edit it's going to be a problem. Use line sequence number instead.

One of my use cases is to copy the value of a field that exists in main line or line sequence number 0 to the other lines/rows. For example, class in the main line to class in line sequence numbers 1, 2, etc.