Oracle is a relational data base (DB).It is a program that use the relational model (proposed in 1969 by Edgard Codd) based on predicate logic and set theory.
Table’s data are treated as sets: so you can have the set of users, the set of employees, the set of books, the set of cars etc.
“Links” between these sets are logical “operation”, are relations between them, and define new sets: the set of books read by users, the set of cars owned by employees.
For the rest of us: Oracle is a system that can read and write data in a very efficient way. What Oracle does is to use files in a very efficient way and to hide this complexity to the final user…to you!
Each time you write a query and access a set (that is read a table’s data) you are telling Oracle to read at least a file.
Each time you write an “expression” that modify a set (that is write, change or delete table’s data) you are telling Oracle to read at least a file.
That’s more or less what Oracle do!
