i am a student and i have a question about database schema , i already created the Entity Relationship Diagram [ERD] and in this step i should do the database schema , must all the entities on my database has a relation between them and the other entities ? i.e : each entity should have a foreign key for the entity before it , because i can create all the tables and only 2 tables can have a relation between them and i control the other tables using C# program i am going to create .
** in my ERD all the entities have a relation between each other .
No. Entities of course can stand on their own. Although in practice if you’re finding that you have very few relationships you’re probably doing something wrong…
You’re sort of right in saying that only two tables can have a relationship but I’d word it as a relationship can have only two participants; tables can certainly relate to more than just one other table.