linq to sql - Working with connected tables using F# linq2sql seqences -

teach me how can improve f# linq2sql seqences

here i'm using linq2sql think got problems it.

and main problem access id here in example i'm making 2 embedded got scary linq2 sql queries because don't know there additional methods or ways make ...

member x.deltaarchive() = // reacting on delta limits     seq { in db.archiveanalogs             d in db.deltas                 if a.id = d.id                     if a.value > d.deltalimit                         yield d.abovemessage                     else if a.value < d.deltalimit                         yield d.belowmessage         } |> array.ofseq 

so complete question : there way make same without using embedded cycles find id conformity ?

thank you.

added :

using :

    <@ seq {for in db.archiveanalogs                 d in db.deltas                     if a.id = d.id                         if a.value > d.deltalimit                             yield a.date, d.abovemessage                         else if a.value < d.deltalimit                             yield a.date, d.belowmessage}          @> |> query |> array.ofseq 

got error :

    following construct used in query not recognised f#-to-linq query translator: call (none,       system.collections.generic.ienumerable`1[system.tuple`2[system.datetime,system.string]] singleton[tuple`2](system.tuple`2[system.datetime,system.string]),       [newtuple (propertyget (some (a), system.datetime date, []),                  propertyget (some (d), system.string abovemessage, []))]) not valid query expression. check specification of permitted queries , consider moving of query out of quotation 

offtopic : must find solution because first google link "f# linq2sql"

first of all, snippet wrote isn't using linq sql. you're running whole processing in memory, because f# doesn't select query operators based on type (as c# does). need mark query explicitly run on sql:

#r "fsharp.powerpack.linq.dll" open microsoft.fsharp.linq  <@ seq { in db.archiveanalogs ... } @> |> query 

an alternative way write want use query.join function (from powerpack). believe following should trick:

<@ join db.archiveanalogs db.deltas (fun -> a.id) (fun d -> d.id) (fun d ->      if a.value > d.deltalimit          yield d.abovemessage      else if a.value < d.deltalimit          yield d.belowmessage ) @> |> query 

(although, think there no difference between using join , nested for - if run on sql optimize join anyway).