Hi, Yep, me again, that pesky person with it's dumb questions. Sorry, about these questions, but I want to know everything and because nobody around me knows something of this stuff, I've to ask you... hope you don't mind too much. If you do, please say! Ok, reading the docs and getting your explenations I see that the choice of database (relational or object oriented) depends on the sort of data to store. Well, I don't get this fully... Suppose we've this data to store : Examination table : Examination, Rooms, FieldX, FieldY, FieldZ Rooms Table: Room, Equipements, FieldX, Subexams SubExams Table: .. .. .. This can be be put in a relational table : Examinations : Exa1, Room1, a, b, c Exa1, Room2, c, d, e Exa2, Room1, d, d, d ... But also can be put in a object-oriented way : Exa1 Room1 a b c Room2 c d e Exa2 Room1 d d d .... So what is the best choice???? Tom.