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Suppose I have the following 3 tables in an Oracle DB:

TABLE1:

Table1Id    Field1    Field2    Field3

With Table1Id as the primary key, but Field1 also being unique and could be made a primary key, even though it isn't defined as such in my DB.

Table2:

Table2Id    Field1    Field4    Field5

With Table2Id as the primary key and Field1 matching the values from Field1 from Table1.

Table3:

Table3Id   Table1Id   Field6

With Table3Id as the primary key and Table1Id matching the value from Table1Id from Table1.

So, I create an entity framework 5 DB-first model (can't do EF 6 because it seems the Oracle model isn't supported yet in that version) and am able to easily create the association between Table3 and Table1, but now I want to create the association between Table2 and Table1.

I found that if I add Field1 as a primary key in Table1 (had to do so by editing the XML for the EDMX file since I otherwise get an error just using the GUI), then I get an issue setting the association since now that there are 2 primary keys, it wants me to map both to fields in Table2. If I leave the association from Table1 > Table1Id as blank and only fill in the association for Table1 > Field1 to Table2 > Field1, I get the a 111 Error.

I am still VERY new to Entity Framework... I hope I explained my question well, but I have no clue how to overcome this... I've seen some answers that say it can't be done in EF4, but is there a way in the later version?

Any help at all (please remember I'm an EF newbie!!) would REALLY be appreciated!!

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John Bustos
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  • Can you add `Table1Id` to Table2? – jamesSampica Jun 26 '14 at 15:41
  • I, unfortunately, have no control over the source DB... I can query it, but **nothing else**... – John Bustos Jun 26 '14 at 15:54
  • It seems to me that you have to declare Field1 as a PK for Table2. You can then set a relation between table1 and table2. But if, in the same context, you need and relation Table1(Field1) Table2(Field1) and Table2(Table2Id) TableX(TableXId), then you are in trouble (except by writing linq query and set the relation by hand through joins) – tschmit007 Jun 26 '14 at 16:36
  • Yeah, thanks @tschmit007, that's exactly the problem... I simplified the problem, but each of these tables is connected to others via their corresponding primary keys... I was hoping there was something I didn't know in EF to do this... As fo rthe Linq solution, I'm guessing that's how I'll go, but then I'm no longer dealing with EF, right? – John Bustos Jun 26 '14 at 16:39
  • in my knowledge, at this time EF does not allow to address simply scenario with 2 PK for a table. I face similar case and, in my case, can use two contexts. – tschmit007 Jun 26 '14 at 16:41
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    if you are in read only, and can create a view, you can use a vTable2 instead of table and build vtable2 to expose Table1Id – tschmit007 Jun 26 '14 at 16:45
  • I like that idea! - Since I have no way to create the view in the DB itself, I used a defining query (http://msdn.microsoft.com/en-us/data/jj730307.aspx). I'm playing around with it now, but could / would this work?? – John Bustos Jun 26 '14 at 18:19

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