CODEWITHSUNDEEP
entity-framework
Justin Rassier
Justin Rassier

Reputation: 908

Entity Framework Conditional Mapping

I have a legacy database that has a table called Address. Now two other tables can have address information assigned to it. To determine which table it came from, there is a SourceID field. If the SourceID is 1 then it is associated with the first table, if it is 2, it is address information for the second table.

This legacy database doesn't have any foreign key constraints defined on the database, and it cannot be added.

I am wondering if I use Entity Framework to create a model that will have this association. Where table 1 can have an entity that has a navigation to address information (with the condition that the SourceID =1) and same with the second table.

I have tried created a conditional mapping and have it set "When SourceID = 1" I also removed the mapping from the column mapping as the column can only be mapped once. When I try to compile, I get the following error:

Error 3004: Problem in mapping fragments starting at line 683: No mapping specified for properties Address.SourceID in Set Addresses. An Entity with Key (PK) will not round-trip when: Entity is type [Model.Address]

Thanks for your help!

Upvotes: 0

Views: 1816

Answers (1)

Ladislav Mrnka
Ladislav Mrnka

Reputation: 364349

Don't use conditional mapping. Map your address to the entity without SourceID property and create two derived entities from the address entity. Use SourceID as discriminator (TPH inheritance - it works same as conditional mapping but you have multiple entities with different discriminator value). Relate your first and second entity to correct address sub entity.

Upvotes: 4

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