[Haskell-cafe] pure Haskell database

[jean-christophe mincke]

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 <marco-oweber at gmx.de> 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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