EXISTS and TABLE ACCESS FULL

 Hello everybody,

I was asked a question about how the EXISTS condition functions in a specific context. 

Given the query "select 1 from dual where exists (select * from trip where trip_id = 6485);", does the whole trip table always get scanned in full, even if a matching record is found before all the records of the table are fetched?

So I searched Oracle's documentation but was unable to find an exact answer. However, the execution plan - when compared to a plan where the table actually gets fully scanned - seems to indicate that the whole table is not necessarily scanned.

Still, I would like to know if their is an "official" answer to this.