Hello,
I've been out of the Haskell game for a bit, but now I'm back. A couple of years ago I made a small library that implements relational algebra with types so that malformed queries and other operations are caught at compile time. It is heavily based off of the internals of HaskellDB (see http://hackage.haskell.org/packages/archive/haskelldb/2.1.1/doc/html/Database-HaskellDB-PrimQuery.html), but types so that it can actually be used directly instead of having to use HaskellDB's query monad. Besides the joy of using relational algebra directly in your code, this also means that you can make query-optimizing code in a type-safe way, you can subquery results returned by the database directly without accessing the database again and you have more options when converting from relation algebra to SQL or another query language. The library isn't quite ready for release, but I might want to work on it a bit and then release it. Is anyone interested in such a library?
Paul Visschers
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Paul Visschers <[hidden email]> wrote:
> I've been out of the Haskell game for a bit, but now I'm back. A > couple of years ago I made a small library that implements relational > algebra with types so that malformed queries and other operations are > caught at compile time. It is heavily based off of the internals of > HaskellDB (see > http://hackage.haskell.org/packages/archive/haskelldb/2.1.1/doc/html/Database-HaskellDB-PrimQuery.html), > but types so that it can actually be used directly instead of having > to use HaskellDB's query monad. Besides the joy of using relational > algebra directly in your code, this also means that you can make > query-optimizing code in a type-safe way, you can subquery results > returned by the database directly without accessing the database again > and you have more options when converting from relation algebra to SQL > or another query language. The library isn't quite ready for release, > but I might want to work on it a bit and then release it. Is anyone > interested in such a library? a library, even though nowadays I mostly use acid-state. Greets, Ertugrul -- Not to be or to be and (not to be or to be and (not to be or to be and (not to be or to be and ... that is the list monad. _______________________________________________ Haskell-Cafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskell-cafe signature.asc (853 bytes) Download Attachment |
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I'd be interested in at least playing with it.
On Saturday, July 7, 2012, Paul Visschers wrote: Hello, _______________________________________________ Haskell-Cafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskell-cafe |
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On Sat, 7 Jul 2012, Paul Visschers <[hidden email]> wrote: > Hello, > > I've been out of the Haskell game for a bit, but now I'm back. A couple of > years ago I made a small library that implements relational algebra with > types so that malformed queries and other operations are caught at compile > time. It is heavily based off of the internals of HaskellDB (see > http://hackage.haskell.org/packages/archive/haskelldb/2.1.1/doc/html/Database-HaskellDB-PrimQuery.html), > but types so that it can actually be used directly instead of having to use > HaskellDB's query monad. Besides the joy of using relational algebra > directly in your code, this also means that you can make query-optimizing > code in a type-safe way, you can subquery results returned by the database > directly without accessing the database again and you have more options > when converting from relation algebra to SQL or another query language. The > library isn't quite ready for release, but I might want to work on it a bit > and then release it. Is anyone interested in such a library? > > Paul Visschers Yes! And yes to first order predicate calculus too! oo--JS. _______________________________________________ Haskell-Cafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskell-cafe |
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Yes, that would be very nice!
Type-checked queries really is a must, but I´ve found HaskellDB too cumbersome to work with. -Rune On Sat, Jul 7, 2012 at 11:45 AM, Paul Visschers <[hidden email]> wrote: > Hello, > > I've been out of the Haskell game for a bit, but now I'm back. A couple of > years ago I made a small library that implements relational algebra with > types so that malformed queries and other operations are caught at compile > time. It is heavily based off of the internals of HaskellDB (see > http://hackage.haskell.org/packages/archive/haskelldb/2.1.1/doc/html/Database-HaskellDB-PrimQuery.html), > but types so that it can actually be used directly instead of having to use > HaskellDB's query monad. Besides the joy of using relational algebra > directly in your code, this also means that you can make query-optimizing > code in a type-safe way, you can subquery results returned by the database > directly without accessing the database again and you have more options when > converting from relation algebra to SQL or another query language. The > library isn't quite ready for release, but I might want to work on it a bit > and then release it. Is anyone interested in such a library? > > Paul Visschers > > _______________________________________________ > Haskell-Cafe mailing list > [hidden email] > http://www.haskell.org/mailman/listinfo/haskell-cafe > _______________________________________________ Haskell-Cafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskell-cafe |
Is this anything like the hssqlppp package?
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> And yes to first order predicate calculus too! Just two weeks ago Chung-chieh Shan and I were explaining at NASSLLI the embedding in Haskell of the higher-order predicate logic with two base types (so-called Ty2). The embedding supports type-safe simplification of formulas (which was really needed for our applications). The embedding is extensible: you can add models and more constants. http://okmij.org/ftp/gengo/NASSLLI10/course.html#semantics _______________________________________________ Haskell-Cafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskell-cafe |
On Tue, 10 Jul 2012, [hidden email] wrote: > >> And yes to first order predicate calculus too! > > Just two weeks ago Chung-chieh Shan and I were explaining at NASSLLI > the embedding in Haskell of the higher-order predicate logic with two > base types (so-called Ty2). The embedding supports type-safe > simplification of formulas (which was really needed for our > applications). The embedding is extensible: you can add models and > more constants. > > http://okmij.org/ftp/gengo/NASSLLI10/course.html#semantics Oleg, thank you. Which article should I read first? oo--JS. _______________________________________________ Haskell-Cafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskell-cafe |
On Wed, 18 Jul 2012, Jay Sulzberger wrote: > > > On Tue, 10 Jul 2012, [hidden email] wrote: > >> >>> And yes to first order predicate calculus too! >> >> Just two weeks ago Chung-chieh Shan and I were explaining at NASSLLI >> the embedding in Haskell of the higher-order predicate logic with two >> base types (so-called Ty2). The embedding supports type-safe >> simplification of formulas (which was really needed for our >> applications). The embedding is extensible: you can add models and >> more constants. >> >> http://okmij.org/ftp/gengo/NASSLLI10/course.html#semantics > > Oleg, thank you. Which article should I read first? > > oo--JS. Ah, I see that the files are Haskell source files, and not Postscript files. The order is clear. oo--JS. _______________________________________________ Haskell-Cafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskell-cafe |
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