Question

Given the following tables I’d like to return the localised text for given culture or the text for the default culture where no row exist for the given culture.

diagram http://lh4.ggpht.com/_gjsCWAV_CZc/ShW6hC-eozI/AAAAAAAACbY/mXaBfiZtBY8/s400/diagram.png

So with the folowing data

Resources

ID  Name
1   Donkey
2   Elephant

LocaleStrings

ID  CultureID  ResID   LocaleText
1   1         1       Donkey
2   1         2       Elephant
3   2         1       baudet

I’d like to be able to return the following for the French culture

baudet
elephant

I’ve tried various queries based around LEFT JOINS samples I’ve seen but I’m stuck.

var ct = from r in db.Resources
                 join lt in db.LocaleStrings
                     on r.ID equals lt.ResID into res
                 from x in res.DefaultIfEmpty()
                 select new
                 {
                     CultureID = x.CultureID,
                     LocaleText = x.LocaleText,
                     ResID = x.ResID
                 };

        var text =
            from c in db.Cultures
            join t in ct
            on c.ID equals t.CultureID into cults
            from x in cults.DefaultIfEmpty()
            select x;

Answer 1

I’m sure there’s a better way, but this seems to work:

    var ct =
        from c in db.Cultures
        from l in db.LocaleStrings
        from r in db.Resources
        where r.ID == l.ResID
        select new
        {
            CultureID = c.ID,
            LocaleText = l.CultureID == c.ID ? l.LocaleText : r.Name,
            ResID = r.ID,
            LSID = l.CultureID == c.ID ? l.ID : 0
        };

    var text =
        from t in ct
        where t.LSID != 0 || (t.LSID == 0 && !((from ac2 in ct
                                                where ac2.LSID > 0 && ac2.CultureID == t.CultureID
                                                select ac2.ResID).Contains(t.ResID)))
        select new
        {
            CultureID = t.CultureID,
            LocaleText = t.LocaleText,
            ResID = t.ResID
        };