Understanding a database schema

Question

This should be a really simple question for any Oracle DBAs out there.

I just started on a new application and I asked to see the schema. I am not familiar with Oracle or its naming conventions at all. So I submit to you the following:

I'd like to know:

• Why the separation from the top 2 fields and the rest? (I assume those are PK but it doesnt explicitly state as much)
• What's the difference from the bolded fields and non-bolded?
• What does 'l3', 'l5', etc indicate?
• A couple other tables (not pictured) have 'U1' indicators where this pic has 'l3', what does that mean?

Answer 1

To answer you questions:

1. The top two fields indicate the primary keys for the table
2. Bolded fields are required ( NON-NULL ) fields
3. "I" indicates that the columns are indexed
4. "U" indicates that the columns have a unique key associated with them

Hope this helps.