Re: I guess I don't know dates

On 28 Jun 2012 09:26, John Yeung wrote:

The big thing to remember about dates is that they are
actually stored as a Lilian* date as a binary integer.

I think it's a little murky to use the word "stored" there. The
*internal* representation is a binary Lilian (or close enough) date.
By "internal", IBM means (approximately) "in memory".

I believe external representations (which are formatted) include not
only displays, but storage in physical files (which is what I think
of when I see "stored"). As mentioned before in this thread, when
you specify DATFMT in the DDS, the field in the physical file will
be sized and formatted accordingly. (As far as I can tell, the
*physical* representation of a date in a PF is identical to the
appropriately edited character string. The only difference being
that the field is declared as type L instead of type A.)

Either that, or a lot of trouble has gone into fooling disk tools
like DSPPFM, DBU, etc.

Indeed, in effect, "a lot of trouble has gone into fooling" the tools. The external representation and DSPFFD effect match, but the internal representation is not externalized [explicitly and clearly]. The database stores the data as a 4-byte binary\integer, but the database returns a /formatted string/ to represent the date value:

IBM i 7.1 Information Center -> Database -> Reference -> SQL reference -> Language elements -> Data types -> Datetime values
_Date_
http://publib.boulder.ibm.com/infocenter/iseries/v7r1m0/topic/db2/rbafzch2date.htm
" ...
Date - 4 byte binary Scaliger number
... "

Regards, Chuck