Re: [Haskell-cafe] relational data representation in memory using haskell?

On Thu, May 22, 2008 at 12:48:42PM +0200, Salvatore Insalaco wrote:

2008/5/22 Marc Weber :

...

So in haskell it would look like this: let updatedCd = 0x22 CD (0x6 "My song") (0x20 ( 0x23 : ...) updatedTrack = 0x23 Track ( 0x21 "updated track title" ) 0x22 in (0x27) DB (0x24 (updatedCd:otherCds)) (0x25 (updatedTrack:otherTracks))

Mmmm I don't think that this is a good way to go. Let me do a counter-example:

data A = A String data B = B String [A] data C = C String [B] data D = D String [C]

A little change like changing the String in A requires updating the whole "DB". You're right. Very bad idea unless you only insert once a year and only have queries the whole day. The only way to fix this is by separating relational data from record data. data A = Map RecordDataA RelationalDataA data B = Map RecordDataB RelationalDataB

So when changing a field in RecordDataA only the relational data B would have to be updated.. but I see that that's not that good either. Fine. Then the only way to go is using uniq ids as keys the way it's already done everywhere Thanks Marc W