One to One

How would I check if a parent in a one to one relation has a child when the child is nullable

Example

where Material.Id and Stock.MaterialId have a one to one association I thougth this:

                var q = Entity.Attribute("Stock") == null;
                var a = u.Find<Material>(q);
would translate to this

        select * from Material

        where NOT EXISTS (select * from Stock where Stock.MaterialId == Material.Id )

also the opposite would be nice

                var q = Entity.Attribute("Stock") != null;
                var a = u.Find<Material>(q);
would translate to this

        select * from Material

        where EXISTS (select * from Stock where Stock.MaterialId == Material.Id )

 Is there a different way to get the same result?

 Did this one get over looked? Or are you guys just real busy about to release a new version?

I beieve this would also apply to any EntityHolder association as in a ManyToOne

I dont think Enity Holder is Query translateable to SQL

I'll have a look into this for you Tommy.

Thanks,

John-Daniel Trask

Hi Tommy,

Try writing your query as:

var q = !Entity.Attribute("Stock.MaterialId").Exists()
var a = u.Find<Material>(q);

To reverse this, drop the ! operator from the query.

I hope this helps,

John-Daniel Trask

You can even save yourself some keystrokes (and keep the query conceptually closer to your original statement) by dropping the .MaterialId:

var q = !Entity.Attribute("Stock").Exists()
var a = u.Find<Material>(q);

I knew it was a mistake letting the marketing guy handle a support query... *grin*

 Hey thanks a million.

Dont you hate it when you try something and it doesnt work but later you find out what you tried didnt work because of a different problem you had since fixed but didnt relate to your previous problem.