fixed default fractional julian day number calculation

[micampe]

This fixes the Julian day calculation I mentioned in #38.

Not entirely sure on the naming I chose, let me know what you think.

Formula deduced from information at https://aa.usno.navy.mil/data/JulianDate

[helje5]

Hm, I think my rational was that one would store a TimeInterval into such. I can see that SQLite uses the Julian day here https://www.sqlite.org/quirks.html#no_separate_datetime_datatype

I'm a bit split on this.

[micampe]

I have no stake in this, I am not using it, I fixed it just because I noticed the discrepancy.

I agree, unclear which choice is the best.

a couple of notes:

• TimeInterval makes sense given the target of this library
• might be confusing for someone using sqlite's date time functions and getting incorrect results
• the default is julian number but can be overridden

[helje5]

Funny enough SQLite always inserts a string for current_timestamp:

CREATE TABLE test ( 
  x TEXT, 
  tt TEXT NOT NULL DEFAULT current_timestamp, 
  rr REAL NOT NULL DEFAULT current_timestamp, 
  ii INTEGER NOT NULL DEFAULT current_timestamp
);
INSERT INTO test(x) VALUES ( 'Hello' );
SELECT * FROM test;
Hello|2024-11-05 17:50:26|2024-11-05 17:50:26|2024-11-05 17:50:26