[Haskell-cafe] Consensus about databases / serialization

Justin Bailey jgbailey at gmail.com
Wed Jan 2 18:22:08 EST 2008


I can speak to haskelldb a little, see below:

On Jan 2, 2008 3:50 AM, Peter Verswyvelen <bf3 at telenet.be> wrote:
> ·        regarding Haskell and databases, the page
> http://haskell.org/haskellwiki/Libraries_and_tools/Database_interfaces
> describes a few, but which are the ones that are stable and practical? Any
> user experiences?

I started looking at haskell database libraries to generate SQL for
me. Haskelldb does this well - it uses a higher-level representation
of queries based on "relational algebra" (also the basis of SQL) which
is pretty easy to understand if you know SQL.  It takes care of a lof
the details of generating SQL strings, and does it in a mostly
type-safe way.

It is a bit complicated to install the library and all its
dependencies, because it can work with 3+ (mysql, postgres, odbc)
databases using two different backends (hdbc and hsql). I chose to go
with HDBC because it compiled on Windows and postgres because thats
what we have at my workplace. Once I got it built and installed its
worked well for me.

Until the most recent versions though, it added a "distinct" operator
to all select statements. I submitted a patch which was accepted and
now that behavior is no longer the default. It is semi-actively
maintained by the original authors and Bjorn, at least, has been very
responsive to my queries on the haskelldb-users mailing list. He also
has made minor updates to keep it compiling with the latest GHC and
Cabal.

Hope that helps!

Justin


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