#1737 Can't retrieve temporals in BC era

[Christian Beikov]

The methods in org.hsqldb.types.HsqlDateTime all fail to account for the ERA when operating on calendars, which prevents reading correct data. If the database has a temporal in the BC era, it always comes out in CE era instead.

In convertMillisFromCalendar and convertSecondsFromCalendar the target calendar also needs to copy over the era like so: targetCalendar.set(Calendar.ERA, sourceCalendar.get(Calendar.ERA));

Similarly in convertMillisToCalendar the like so: calendar.set(Calendar.ERA, tempCalGMT.get(Calendar.ERA));

resetToDate and resetToTime should probably also do cal.set(Calendar.ERA, GregorianCalendar.CE);

[Fred Toussi]

Hi Christian,

For dates (and timestamps) I followed the SQL Standard which allows 0001 to 9999 for the year and does not allow BCE values. This is enforced in date-time literals which do not allow BCE values. When using assignments via Java PreparedStatement etc. and arithmetics involving INTERVAL there is no range checking.

[Christian Beikov]

One can produce BC timestamps with to_timestamp('BC 0001-01-01 00:00:00', 'BC YYYY-MM-DD HH:MI:SS').

[Fred Toussi]

For future reference, it's good to know where there are no checks. Still, literals such as DATE 'BC 0001-01-01 00:00:00' are not allowed