[plt-scheme] Database Connectivity Role Call

From: Hans Oesterholt-Dijkema (hdnews at gawab.com)
Date: Fri May 18 04:45:17 EDT 2007

There's also the sqlid framework. It was first released with
a number of drivers: DB2, Oracle, MySQL, PostgreSQL, Sqlite.
But these drivers all needed to be compiled on the target platform
and that posed problems.

Corey Sweeney wrote sqlid-helper.plt that "schemes" the SQL
that has to be written in strings for sqlid.

However, in sqlid it is possible to pre-write SQL expressions and
store them under a key. This separates SQL from code. One just
calls sqli-exec with a key and parameters.

I've recently separated the SQLID package from the SQLD drivers.
There are currently two: sqld-sqlite.plt (FFI based) and sqld-psql.plt
(spgsql based). A sqld-mysql is being prepared but will take some

FFI based oracle and db2 drivers could be made, however the FFI
has no way to asynchronously call functions and mzscheme has no
OS threads. So SQL queries via C will very often block scheme.


Grant Rettke schreef:
> Hi folks,
> May you please reply to this post if you are actively or have actively
> used in the past a particular database connectivity library with PLT
> Scheme, and the name of that library?
> I am more interested in folks vouching for libraries in particular
> rather than just pointing me at Planet.
> I have already bugged Noel about PostgreSQL enough on this one, so one
> thing I do know is that PLT Scheme and PostgreSQL work very well
> together!
> Platform is also interesting, for example, if ODBC on Windows versus 
> on UNIX.
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