You do not need know much about the backend system setup.
You need to know well of how to get the DATA from database and how to generate your reports.
From network sside, as long as you know how to configure tnsnames.ora (to connect database from your client machine), or ask your DBA how to do it, that's enough.
From system side, Unix SA and DBA will take care to have enough CPU and Memory to run the database, you do not need worry about that.
Again, there are many industry need your skill (not only high Tech companies, but also low tech service companies). This is the beauty whay I encourage people learn something asoociated with database.
Thanks!Thanks!