Wrong date in database.

Question

Last I was programming and something strange happend. I made the following statement:
"INSERT INTO nietzwemmers(leerling_ID, datum)  VALUES("+IDs[i]+", "+sdf.format(new java.util.Date())+")"Everything goes well, until I go and look in my database. There I don't find the date of today, but the date of somewhere in 1905. Strange, milenium bug you say, thought that too, but no. On a recent computer I have the same problem. And I know that the problem lays in the jdbc:odbc connection , or even later, because when I print the date in the console, the correct date is displayed.
Anyone an idea?
P.S. I use Win XP, a recent java version, 1.4.*, and mircosoft acces some version.

Answer 1

You're having these problems because you're passing either a numeric representation of a date, or a string representation of a date, and the driver and/or database is doing implicit datatype conversions for you from number to date or string to date. The conversion rules change depending on wheter you start with a number or a string.
You can avoid these sorts of type conversion problems by using PreparedStatement, and sending the database an actual Date, and thereby avoid dependencies on implicit conversions (and the work of converting it yourself only to have the driver convert it back).
This might not work with Access (I've never tried it with that), but it really should, it works on most real databases...
// prepare the statement outside the loop
final String sql = "INSERT INTO nietzwemmers(leerling_ID, datum)  VALUES(?, ? )"
PreparedStatement pstmt = connection.prepareStatement(sql);
// do this outside the loop if you want all records from array ID to have the same time
// do this inside the loop if they should have the exact moment the
pstmt.setDate(2, new java.util.Date() );
// loop through the values of i...
while ( ....
  // Long or Int or whatever numeric type is appropriate
  pstmt.setLong(1, IDs);
pstmt.execute();
A nice side effect is that it can drastically reduce the amount of temporary strings that are generated, thereby reducing the amount of time spent in garbage collection. (Whether it actually does or not depends on the driver implementation.)