I still don't understand whether term data model (or data model
instance) refers to mechanism ( implemented as software ) that defines
what kind of structures ( tables, relationships etc ) system
administrator can create using SQL statements, or does the term refer
to actual structures the system administrator created using SQL
statements?
For example, say I create ( in relational database ) a new database
consisting of one ( or more) table. Now does term logical data model
refer to this very table I created, or does the term relate to
mechanism that defines what kind of structures ( in relational DB ,
for example, this mechanism allows table structures ) we can create
and what kind of connections we can establish between these tables?
2)
And how does a scheme fit into all of this?
thank you
