Scala Slick table tag

Question

In slick table there is a tag parameter:

class Companies(tag: Tag) extends Table[Company](tag,"COMPANY") {...} 

What is it used for, and is there any way not to write it with each table class definition?

Answer 1

The best answer I've seen is: https://stackoverflow.com/a/27783730/154248

What's it used for: imagine you needed to join a table on itself. That tag is a way to distinguish between the tables taking part in a query.