2008/6/20 Alistair Bayley
Is there a way of accessing a remote Oracle database by one of the common Haskell database interfaces (HaskellDB, Takusen, etc.) ? I tried to get unixODBC and Oracle's Instant Client running on a Linux machine, but I'm trapped in the notorious error:
Takusen's Oracle backend uses the Oracle Call Interface (OCI) library directly. I think most Oracle client drivers (ODBC, ADO.Net, etc) use the OCI. I don't know what the Oracle Instant Client is; I'll assume that it includes an oci.so or liboci.so. On Windows, with which I am most familiar, the Oracle client software is all installed in $ORACLE_HOME, and the OCI library is $ORACLE_HOME/bin/oci.dll. If you can locate that, then you ought to be able to use Takusen with it.
Having just taken a closer took at what Oracle Instant Client is, I suspect that you might have some trouble getting Takusen to compile against it. The Instant Client lacks header files, while Takusen's FFI imports specify oci.h. I don't know what happens if ghc can't find the header files. Oracle do state that the Instant Client is for deployment only; developers (that means you) will need the full client installation. Another problem is that the Oracle installation process assumes that, for all platforms, the library is called oci i.e. the linker option -loci is used. For Unix clients, the OCI library seems to be libclnstsh.so, so I guess it should pass -lclnstsh. This highlights the lack of testing on non-Windows platforms. If you'd like to help get this working better, perhaps we can discuss off-list. Alistair