Hehehe. I first learned about the importance of date field ordering as Freshman in college taking my first C.S. class. For humans, whatever is most common in their part of the world works best, except on government forms, where whatever format the government dictates is by far the safest.

More seriously, by using YYYYMMDD (just strip out the "/"'s or "-"s in your software if need be), you can then sort the items in question by date in ascending or descending order with minimal extra work.

Years include months which include days and most of the Western world uses Arabic numerals for math and has the most significant digits to the left. There are standard libraries in the oldest and newest (well supported) programming and scripting languages to handle dates as ASCII or EBCDIC text strings, BCD numeric fields, or binary integers.

Without getting into the whole Big- versus Little-endian argument as to how most and least significant bits are stored in Hi and Lo bytes in 16-bit CPU registers, etc. (which annoys even those of us who love low-level programming), I've found that on any serious CPU made since Y2K, just converting a date inputted as YYYYMMDD into a big integer lets one add an HHMMSS time stamp as another integer to the right of a decimal point which is used more as a delimiter than a means of making the resulting floating point number ready for meaningful mathematical operations.

If a lot of caclulations are going to be done with dates (and/or times) and the number of things with date stamps is large (millions or more), storing the date and time as integers can greatly speed up the processing. If sorting is only thing done with dates that involves their value being used by the computer except for I/O, then saving them as ASCII makes life easier, and going with BCD can cut the storage those dates take up in half and requires just trivial conversions for I/O.

FractalZ