AUBIT and Microsoft SQLServer
Database connection
Making a good ODBC connection from Linux proved a major problem, especially on a Debian box, but eventually all came good when we installed unixODBC 2.2.11 and freeTDS 0.6.3. Both of these we had to get from Debian testing; earlier versions in any combination were unsatisfactory.
General results
A test program showed that everything then worked, without any need for special environmental variables - scroll cursor, fetch next, fetch previous, foreach, select count(*)/fieldvalue into ... The scroll cursor in particular was a surprise, since the freeTDS documentation says that scroll cursors are not in the game plan.
Problems with database object names
Further down the road, with more complicated expressions, more problems arose. Mixed case in the SQLServer database object names forced us to PREPARE SQL statements, since the treatment of quotation marks by the SQL conversion routines was not yet sufficiently reliable to declare cursors directly. The database in question did not contain spaces in the object names, so treatment of these remains untested. If they occur, SQL conversion may not be satisfactory, and native SQLServer syntax may have to be used.
Problems with JOIN
In statements involving a JOIN condition, it was found necessary to fully qualify every field name (tablename.fieldname), in every instance. Without this, error messages were erratic; and were equally erratic, but quite different, if the same statements were submitted either via unixODBC's isql or via OpenOffice.org Base. The use of aliases was also abandoned in order to minimise parsing problems. This results in hideously verbose statements; but they work.
SQL Conversion
The INFORMIX-SQLSERVER.cnv was found to be fully satisfactory, (outer joins not yet tested), so standard INFORMIX syntax works as expected. Native SQLServer syntax is also ok, with or without conversion being active.
Please Note
Aubit Computing Ltd, in conjunction with its partners, are able to offer a full conversion service for migrating Informix4GL applications to the Microsoft™ .NET platform.
If you are interested in porting your 4GL application to .NET, running against either an Informix™ or Microsoft™ SQL Server Database - then please contact sales@aubit.com
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