Why does Database First EF skip mapping some tables?

Question

I'm using Entity Framework 4 and with a Database First binding, and EF is not generating the entities for a few of my tables. I'm not getting any errors, and no matter how many times I select the tables to generate from the "Update Model from Database" popup menu on the design surface, the same tables are still missing from the model.

I get no errors in the wizard. They just don't get generated. Any clues?

Forever

Does those table have primary key in them? – Janssen

@Akash, that might be the pattern. Looks like all the fields in those tables are nullable, so EF probably can't presume a PK value. If you want to convert your comment to an answer I'll accept it. – Forever

Answer 1

EF requires a primary key on the table. EF will not map tables for which it can't find or derive a primary key. If all columns are nullable, it can't assume a primary key. If one or more columns are not nullable, EF will evidently derive a primary key for the table.

Forever

Answer 2

EF will ignore table without primary keys.

Janssen

Minor clarification - EF will not map tables for which it can't find or derive a primary key. If all columns are nullable, it can't assume a primary key. – Forever

No EF has no problem with nullable columns, it only checks for primary key. And primary key can not be nullable, so condition for nullable is not considered. – Janssen

Well, all I can say is try it. If ALL columns are nullable, the table will silently fail to map. If you have one or more columns are not nullable, it derive a primary key and map the table. – Forever

Derive primary key from where? – Janssen

Answer 3

Options I can think of:

• Did you check the box next to those tables?

• Did you previously add them, then delete their entities but keep the cache of the tables?

• If so you can remove them from entity browser window and re-add them or manually add entities and define the table they map to in mappings window.

• Perhaps tables were classified as relations instead of entities?

• You can manually add the entities and choose the table they map to in mappings window.

Hove

Thanks for your reply, Danny. As I indicate in my question, I have repeatedly tried to remap them via the wizard, and they never map. I also select all tables to bind in the model when originally creating the model, too. I can probably create manual mappings for them if I have to, but that doesn't answer the question of why they don't get mapped in the first place, and also doesn't bode well for updating the model from the DB in the future. – Forever

Try adding a new entity from toolbox, not from wizard and map it. – Hove

Answer 4

A possibility is when you're using tables with some different field types, as hierarchy in SQL Server.

Amatory

Answer 5

Actually, in my case, it doesn't work because I was using a hierarchyid field as a primary key and EF doesn't work with this field type, so, it didn't import the table, because a valid PK is required.

Amatory

Answer 6

Without Primary Key Tables where Skip Automatically on EF, OtherWise You Fix a Value as Not Null.

Tref