Re: File Last Changed

[CRPence <crp@xxxxxxxxxxxxxxxxxxxx>]

  Using DFU to change a row is both a /change/ and a /use/.  The /use/ 
is from the Open, and the /change/ is from the Update record operation.

  Database *FILE objects are merely a container for *MEM [member; noted 
sometimes instead, as *MBR] objects.  They are even presented as a 
directory when viewed from the IFS.  To know the usage information of 
the data, drilling down to the members is required.  A 'change' is not a 
'use' of an object.  A 'use' is defined by action(s) which define the 
existence of the object; i.e. define its purpose in life.  For the 
database file object, its existence is defined by access to the member 
data; its purpose is to allow the storage, retrieval, removal, and 
update of the data within its members.  Without data, a database file 
has little value [except as a reference file; Hmmm, I wonder if that is 
being manifest as a 'use' -- probably should be].  Thus, unless the data 
is referenced by an operation, that operation is not considered to have 
/used/ the member.  An object-level change for any object type that 
encapsulates data is not limited to being [identified as] /changed/ 
solely due to changes to its data.  Moving or restoring the object, 
changing its authority, owner, text, attributes, etc. are all changes. 
As such, there is not any solid relationship to /use/ and /change/ 
date-time; the use could easily & validly be two years prior.

  The /change/ of the database file, from the perspective of changing 
data in any one member, is [effectively; it may be updated more] limited 
to its first change since the last save; i.e. whatever adds the object 
to the list of objects eligible for /save-changed/ processing.  This is 
really only a convenience for the DSPOBJD, as the arbiter of change and 
usage is really the members; again, the file as /container/ -- just as 
changing a file in a library does not signify a change to its library. 
For changes to the data, there are both 'source change date' and 'change 
date' information to consider, if the *FILE is a database _source_ file.

  Any decision about the use and change of database files really needs 
to decide for any individual member first, and then if the only/last 
member is eligible for removal, then so too the *FILE may be eligible.

Regards, Chuck