On Wed, Apr 4, 2012 at 7:59 PM, MightyByte
pranjal pandit
writes: Hi,I would like to work on improving the HDBC as a GSOC project 2012. I have a previous working experience with Django and its ORM and I had a look at Amnesia (http://amnesia.sourceforge.net/user_manual/manual.html) which is a SQL database interface for Erlang.
Few of the features of both include: 1 ) Database operation are supported through Language Native types. 2 ) Direct table creation from native language constructs.
Hi Pranjal,
Here are some things to consider when writing your proposal.
Haskell RDBMS libraries exist on two different broad levels of abstraction. There are low-level libraries that provide the ability to write raw SQL queries and retrieve the results, and there are high-level libraries that do more sophisticated things. These high-level libraries are more of what you're probably thinking about when you think ORM. HDBC and others like mysql-simple, postgresql-simple, etc are in the low-level category. The high-level category has libraries like haskelldb, persistent, and groundhog.
In some cases the high-level libraries are written using a low-level library as the back-end. Haskelldb is a good example of this because it uses HDBC for its low-level access. HDBC provides a uniform interface for working with MySQL, PostgreSQL, and SQLite so by using HDBC, haskelldb works with all these databases for free. However, some high-level libraries like persistent don't use a separate low-level library and instead opt to maintain their own code for interfacing directly with the database.
This isn't exactly true. persistent-sqlite has its own low-level layer based on direct-sqlite[1], but the other three backends each use an existing low-level library (postgresql-simple, mysql-simple, and mongoDB). Michael [1] http://hackage.haskell.org/package/direct-sqlite