Marc
What is this strange syntax
columns = [ ("trackId", conT *''Int* )
It looks like a not ended string literal unless I still have sth to learn
about Haskell.
Thank you
J-C
On Thu, Sep 25, 2008 at 12:03 AM, Marc Weber <[EMAIL PROTECTED]> wrote:
> On Wed, Sep 24, 2008 at 11:17:01PM +0200, Manlio Perillo wrote:
> > Hi.
> >
> > I need a simple, concurrent safe, database, written in Haskell.
> > A database with the interface of Data.Map would be great, since what I
> need
> > to to is atomically increment some integer values, and I would like to
> avoid
> > to use SQLite.
>
> I've tried writing at least part of that. But it's still higly
> experimental and uses template haskell.
> It looks like this:
> from that some datastructures are defined which look like
> tables used in traditional RDBMS such as SQLite..
> However if you don't want to use many "tables" you may be a lot faster
> writing down what you need yourself. My lib automacially generates code
> for inserting / deleting tuples into multi indexes such as (Map Int (Map
> Int PrimIdx)).
>
> $(let cds = defaultTable {
> tblName = "cds"
> , columns = [ ("cdId", conT ''Int) , ("title", conT ''Int) ]
> , primary = PrimaryUniq [ "cdId" ] [| 0 |]
> , indexes = [ Index "title" [] ]
> , tblStates = [ ( "nextCdId", [t| Int |], [| 0 |] ) ]
> }
>
> tracks = let
> a="a"
> -- updateNumRows n = [| \n -> cdUpdateByPK (\r -> r {
> num_tracks = (num_tracks r) + $(n) } ) |]
> in defaultTable {
> tblName = "tracks"
> , columns = [ ("trackId", conT ''Int )
> , ("name", conT ''String)
> , ("cd", conT ''Int) -- foreign key
> ]
> , primary = PrimaryUniq [ "cd", "trackId" ] [| 0 |]
> , indexes = [ Index "cd" [ IndexUnique "trackId" ] ] --the id
> is uniq foreach cd
> -- checks = [ foreignConstraint "cd" "cds" "id" ]
> -- triggers = [ InsertUpdate (Just ["cd"]) [| cdUpdateByPK (
> updateNum_tracks (+1) ) . pk |]
> -- DeleteUpdate (Just ["cd"]) [| cdUpdateByPK (
> updateNum_tracks (-1) ) . pk |]
> -- ]
> }
> db = defaultDB {
> dbName = "my"
> , tables = [ cds, tracks]
> , statistics = True
> }
> in createDB db)
>
>
> If you're interested drop me a mail.
>
> Marc
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