Linq2Entity Getting Values from reference Table

问题

i have 3 tables

Table: A - aID - Text

Table: B - bID - Text

Table: A_B (reference table which holds both of the primary keys as foreign keys) - aID - bID

The Entity Framework knows that Table A_B is just a reference table and does not create it in the DBModel but keeps the references in Table A and B.

My question is how do i get the data which is in the reference table without actually having this table? When i try to access the values of Table B using the reference which is in Table A i cant get the values of the Table B Colums.

        ObjectQuery<A> aTable = dbConnection.A;

        var result = from data in aTable
        where data.aID = '12'
        select data.B; //B is the reference to table B out of table A

What i need is something like:

        ObjectQuery<A> aTable = dbConnection.A;

        var result = from data in aTable
        where data.aID = '12'
        select data.B.bID;

How do i get data out of Table B using the reference between Table A and Table B?

Using: VS 2010 Prof, .Net 4, Linq2Entity

回答1:

As Gary Said, you either use First (if you want one B for each A), FirstOrDefault (if you want nulls where there is no B for A) or SelectMany (if you want all Bs for each A) The latter can be written like this:

 var result = from data in dbConnection.A
              from b in data.B
              select b.Id;

来源：https://stackoverflow.com/questions/9162844/linq2entity-getting-values-from-reference-table