I have a table Messages with columns ID (primary key, autoincrement) and Content (text). I have a table Users with columns username (primary key, text) and Hash. A message is sent by one Sender (us...

I was only able to find the following two differences: The relationships in an E-R model are explicitly defined, while they are implicit in a relational model. Relational models require an interm...

I have created a relation between User, Property and junction table of these two items UserPropertyJunction which can be visualized as releation in the image below UserEntity, instead of customers...

I have three tables, of which 2 are regular data tables and 1 is a many to many junction table. The two data tables: table products product_id | product_name | product_color --------------------...

I have the following model public class PageConfig : Base { // Properties Etc.. public ICollection<Image> ScrollerImages { get; set; } } My approach is to bind using a junction table { ...

According to the definition, a Junction Table (bridge table/link table) is used for many-to-many relationships, when used like this: CREATE TABLE Users ( UserLogin varchar(50) PRIMARY KEY, UserPas...

I'm using Microsoft SQL Server Management Studio and while creating a junction table should I create an ID column for the junction table, if so should I also make it the primary key and identity co...

I'm modeling many-to-many relationship where the relationship is accessed most of the time from one side only. It's more like a hierarchy, that is accessed top-down and not the other way arou...

Using Entity Framework/LINQ, I need help with the following. The database has a table of People with an identity column of PersonId. There is also a Skills table with an identity column of SkillId...

create_table :categories_posts, :id => false do |t| t.column :category_id, :integer, :null => false t.column :post_id, :integer, :null => false end I have a join table (as above) with ...

I'm trying to create a many-to-many relationship in Entity Framework (code first), according to the following post: Database design for limited number of choices in MVC and Entity Framework? Howev...

Let's say we have a Product table, and Order table and a (junction table) ProductOrder. ProductOrder will have an ProductID and an OrderID. In most of our systems these tables also have an autonum...

I have read several tutorials on what a UML model should contain and what it shouldn't. As a developer, I always think in terms of a relational data model where you could never have a many-to-many ...

I was watching a screencast where the author said it is not good to have a primary key on a join table but didn't explain why. The join table in the example had two columns defined in a Rails mig...