At what ANSI/SPARC level are you, when creating new... totally lost

I just started learning about databases and already I'm totally lost

1. When you use,for example, SQL statements to create tables and implement relationships with primary and foreign keys, do you operate at level three ( internal/logical model ) of ANSI/SPARC architecture, or at level 2 ( conceptual model )  Thus, by creating a new database are you creating logical model or conceptual model?

2)
Also, if in, say relational database, model created by administrator
( by defining new tables and keys ) is called logical model, then at
what ANSI/SPARC level is relational model at? Since relational model is actually a set of rules to which all of the above models
( external, conceptual and logical models ) in ANSI/SPARC architecture
comply, relational model should be below logical model, but problem is that ANSI/SPARC only defines three level ( four, if we include actual physical level )

3)
What is the difference between model and scheme?

thank you Received on Sat Jul 14 2007 - 00:23:24 CEST