FreeTDS Development Group

[Jason Goemaat <jasong AT netins.net>]

Client: JDK 1.1 and 1.2 on Windows NT and Solaris
Server: Sybase Adaptive Server Enterprise 11.5.1 on Solaris

I came across a problem with getting dates from a JDBC ResultSet.  Sybase 
doesn't have a Date column, just datetime. FreeTDS_jdbc gets the value as a 
long and creates a Timestamp from the value stored in Sybase.  The problem 
is that our Syase server stores the datetime values as offsets from 
1/1/1970 in the current time zone, not as GMT.  Seeing as other software, 
the JDBC-ODBC bridge, and Sybase's JConnect driver all returned Date 
objects with the correct date and time in them, I decided to change 
FreeTDS.

I made the following modifications to Tds.getDatetimeValue():

Snippet of fixed code:
//---------- begin code ----------
         case 8:
         {
            // It appears that a datetime is made of 2 32bit ints
            // The first one is the number of days since 1900
            // The second is the number of seconds*300
           // JLG - To account for timezone differences
           TimeZone tz = TimeZone.getDefault();
           int offset = tz.getRawOffset();

            int    days    = comm.getTdsInt();
            int    time    = comm.getTdsInt();
            long   seconds = (long)((days - 25567)*(24*60*60))
               + (long)(time/300);
            Date d = new Date(seconds * 1000 - offset);
            if (tz.inDaylightTime(d))
              seconds -= 60 * 60;

            result = new Timestamp(seconds * 1000 - offset);
            break;
         }
//---------- end code ----------

Snippet of original code:
//---------- begin code ----------
         case 8:
         {
            // It appears that a datetime is made of of 2 32bit ints
            // The first one is the number of days since 1900
            // The second is the number of seconds*300
            int    days    = comm.getTdsInt();
            int    time    = comm.getTdsInt();
            long   seconds = (long)((days - 25567)*(24*60*60))
               + (long)(time/300);

            result = new Timestamp(seconds * 1000);
            break;
         }
//---------- end code ----------

The timezone offset is added to the date and if the date is in daylight 
savings time in the default timezone, another hour is subtracted.  I've 
tested this quite a bit and it seems to work great.

Jason Goemaat
jasong AT netins.net