CODEWITHSUNDEEP
c#.netlinq
TomL
TomL

Reputation:

LINQ table join with entity Framework

In my database I have ... TableA, TableB and TableC

TableB has just 2 columns, the primary key of TableA and TableC, so it really defines a one to many relationship between the two tables

What I want to do using SQL is:

SELECT * 
FROM TablesA a
JOIN TablesB b ON a.AID = b.AID
WHERE b.BID = 1

In the Entity Framework it doesn't create a TablesB for me to do the join, I think because TableB only has foreign keys!

So how can I do it?

Upvotes: 9

Views: 17948

Answers (2)

Puzzled
Puzzled

Reputation: 378

When you import the tables from database, entity framework gets rid of the TableB table and shows TableA and TableC to have many to many relationships. TableA has a navigation property TableCs and vice versa. So all you need to use these navigation properties, for sample:

var tableARow= db.TableA.First(s => s.Id == 1); 
if (!tableARow.TableCs.IsLoaded) { tableARow.TableCs.Load(); }

or 

var tableARow= db.TableA.Include("TableCs").First(s => s.Id == 1);

Upvotes: 3

Rex M
Rex M

Reputation: 144112

Doing a join with LINQ is fairly straightforward

from a in TablesA
join b in TablesB
on a.AID equals b.AID
into joined
where b.BID == 1
select joined

I think the real question may be - why don't you have an entity class for TablesB? We may need more information to answer that.

Upvotes: 8

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