Hints on creating a .NET driver

A .NET driver could mean two things:
1) 100% C# (or any other language supporting the Common Language 
Runtime), meaning a reimplementation of the network protocol.

2) something that can be called from any .NET language but which could 
be implemented in C/C++.

Of course there are variations possible, just like the SAP DB Java 
driver, where an optional DLL implements shared memory communication, 
which is not accessible from 100% Java.

1) For those willing to take the $5000 offer: writing the JDBC driver 
took me about 1 month. The result was usable, but of course it contained 
many bugs and misunderstandings of the spec. And I knew the network 
protocol quite well.

Don't start with the JDBC driver. The network protocol is partly defined 
through Pascal records (see sys/src/vsp001) and these have no equivalent 
in Java and have been simulated by code like 'get two byte integer at 
offset x'. Start with the documents in 
http://sapdb.2scale.net/moin.cgi/NetworkProtocol. Write example programs 
for an existing interface (possibly the .NET ODBC bridge) and look at 
the vtrace.

2) There exists now a C++ API that will form the basis of future 
implementations of the Precompiler, ODBC and possibly a less portable, 
but faster JDBC driver. The sources are in 
sys/src/SAPDB/Interfaces/Runtime and sys/src/SAPDB/Interfaces/SQLDBC, 
documented by doxygen comments (sys/config/interfaces/doxygen).

Daniel Dittmar

-- 
Daniel Dittmar
SAP DB, SAP Labs Berlin
[email protected]
http://www.sapdb.org