FreeTDS Development Group

[James K. Lowden <jklowden AT speakeasy.org>]

All, 

I tested the dbconvert() tonight.  I thought you might be interested in
what I found.  

Executive summary: B+.  No segfaults.  Mostly correct outcomes when the
return code indicates success.  Unexotic conversions mostly succeed. 
Failures trigger the error handler with oh-so-helpful messages.  

You can reproduce my results if you like, by looking at this page:

http://www.SchemaMania.org/freetds/cvs/freetds/src/dblib/unittests/

You need: convert_acid.c and eg_handlers.h
also:     convert_acid.make (a shell script)
and       convert_acid.output (my results)
and       killer_query.sql 

The query returns one row of 18 datatypes.  The program executes a query
(from stdin) and attempts to convert each value in the result set to every
known datatype.  It consults dbwillconvert() first, and doesn't attempt to
convert incompatible types.  

Anyone think any of this should be in cvs?

== the results (with TDS 5.0) ==

Forget Binary, image, numeric, and decimal.  They're mostly broken.  

input           status  comment
=====           ======  =======
char            OK      No numeric/decimal, no money. 
text, varchar   Perfect!
bit             OK      No numeric/decimal. 
tinyint         OK      No numeric, image.
int, smallint   OK      No numeric/decimal, image/binary.
real, float     fair    No numeric, image, integers; maybe money.  
datetime        OK      No image/binary.
smalldatetime   OK      No image/binary.
money           fair    No numeric, image, integers.  
money           wrong   float & real yield -283649471676416.
smallmoney      OK      No numeric/decimal, image/binary.       
smallmoney      odd     201203.04 -> real yields 201203.046875 
numeric         broken  char/varchar only. 
decimal         broken  char/varchar, float/real only.
timestamp       broken  char/varchar only. 
image,varbinary broken  char, text, binary only.  

== conclusions ==

0.  Everything can be made into a char/varchar!
1.  Money needs attention.  Should convert to int, should correctly
convert to floating point.  This is just a debugging effort; the code is
there.  
2.  What happened to float -> int? 
3.  Numeric/decimal is not ready.  

As far as I'm concerned, 1 & 2 have to work in 0.60.  Numeric is the other
big hole, but I don't consider it essential.  I know, I've many times said
"any<->any in 0.60".  I wasn't thinking about legal weird conversions like
"datetime<->image".  If we crossed those three items off the list (as
done), I'd consider the job complete.  

And, if someone wants to make numeric work in 0.60, you've still got a
couple of weeks! 

The mere fact that my testing was worth bothering with is evidence of how
far we've come.  I'm going to return to updating the UG in preparation for
our release.  As soon as money works, I'll arrange a pre-release.  

I hope you're having fun.  I sure am.  

Regards,

--jkl