CODEWITHSUNDEEP
c#.netsql-serverentity-framework
Amberite
Amberite

Reputation: 1409

Entity Framework Code First configuration with multiple one-to-many relationships pointing to a single table

I am building an application with many different objects (tables), many of which have a need to have a one-to-many relationship to an "Attribute" object. For example, I could have five different objects - A, B, C, D, E - and each of these needs to have an Attributes property - A.Attributes, B.Attributes, etc.

My question is, how would be the best way to structure this in EF Code First? This Attribute class may end up having 15-20 different classes that have a relationship with it.

Currently, a configuration for one of the "parent" classes looks like this:

        HasMany(rdp => rdp.Attributes)
            .WithOptional()
            .WillCascadeOnDelete();

However, this will create a foreign key column on the Attribute table (e.g., "A_Id", "B_Id", etc). So if I have 20 different classes with attributes, the Attribute table will have 20 different foreign keys.

Is there any better way to structure this?

Upvotes: 3

Views: 931

Answers (1)

Olav Nybø
Olav Nybø

Reputation: 11568

You could introduce an AttributeList type that maps to its own table. I.e. you could model the list as an entity.

A, B, C, D, E would have a one-to-one association to the AttributeList, with the foreign key to the AttributeList on the A, B, C, D and E classes.

Each AttributeList object contains many attributes, or in other words there is a one-to-many relationship from AttributeList to Attribute.

Now you have a single type with one-to-many to the Attributes and you only need a single foreign key to the AttributeList on the attributes.

Upvotes: 2

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