I'm working on designing my very first actual database from the following UML class diagram (in French unfortunately):
I'm at the point of creating the relational sketch of it which I created this way:
Yet, it creates some issues when trying to ask to the database which are the clients that never ordered product number one?
Indeed, I don't know how to do it in SQL as far as it seems that there is no relations between Client, Commande and Produit. It gived the following sql code:
CREATE TABLE Client ( IDClient INT NOT NULL, AdresseClient VARCHAR(255)NOT NULL , NomContact VARCHAR(255)NOT NULL, NumeroSIRET VARCHAR(14) NOT NULL, CONSTRAINT cclient PRIMARY KEY (IDClient) ); CREATE TABLE Produit ( IDProduit INT NOT NULL , PrixVente INT NOT NULL , QuantiteEnStock INT NOT NULL , CONSTRAiNT cproduit PRIMARY KEY (IDProduit) ) ; CREATE TABLE Commande ( IDNumeroCde INT NOT NULL , Date DATE NOT NULL , CONSTRAINT ccommande PRIMARY KEY (IDNumeroCde) );
In relational algebra and calculus it gives:
The fact that I can't explain it in relational calculus let me think that I've done a mistake.
Edit with the new tables
I read all the links you provided and therfore add some comments and changes on my tables, can you tell me if I'm right on my assumptions?
But the last ones have the same primary key then. is it a problem?