Question

I have two tables. Linked with a foreign key.

Now I fetch a row from the field table:

IField Field = from f in DataContext.fields
               where f.mapId == mapId && f.x1 == x && f.y1 == y
               select f;

Working with this row I need some data from the linked table fieldViews. So I just do somthing like this:

[..] Field.FieldViews [..]

According to the SQL Profiler Linq To Sql generates the following queries.

SELECT
    [t0].[fieldId],
    [t0].[mapId],
    [t0].[x1],
    [t0].[y1]
FROM
    [dbo].[fields] AS [t0]
WHERE 
    ([t0].[mapId] = @p0) AND 
    ([t0].[x1] = @p1) AND 
    ([t0].[y1] = @p2)


SELECT
    [t0].[fieldViewId],
    [t0].[fieldId],
    [t0].[mapUserId]
FROM
    [dbo].[fieldViews] AS [t0]
WHERE
    [t0].[fieldId] = @p0

But I don’t want 2 queries. How can I make LinqToSql to include this linked object within the first query?

Answer 1

Using the DataLoadOptions you can specify that L2S will load the FieldViews records together with the Fields.

Insert something like this before the query:

var dlo = new DataLoadOptions();
dlo.LoadWith<Fields>(f => f.FieldViews);
DataContext.LoadOptions = dlo;

The server will execute two queries, but within the same call to the server.