[REBOL] Re: possible data format ... Re: Re: dbms3.r 01
From: greggirwin:mindspring at: 16-Jan-2002 11:50
<< Maybe I don't think so anymore :-) I talked the problem with my
and Michael suggested, that any kind of locking, is done in memory. We found
interesting document though, which describes several scenarios, even one
lock field and time stamp ....>>
But for this to work, you need some kind of file locking mechanism (e.g.
SHARE under DOS), or shared memory, correct? I.e. if you have two separate
dbms scripts running against the same file, how do they communicate lock
information if REBOL doesn't give us the ability to "flag" locks against
specific file offsets?
<< http://www.rebol.cz/~asko/xbase.txt - very cool description .... >>
<<RE: rec-num: ...in XBase, it has its meaning. You can open dbase file
without opening any index,
so browser sorts records according to their rec-no. >>
Right, if we have access to a block of records, whether as a complete file
on disk or as the result of a query, there would be an implied order to
them, but I see that as separate from a record identifier (its GUID).
<< I think that it depends upon what your intention is - do you want to have
variable column records? I would not suggest it, as it is a little bit more
difficult for any kind of anylysing software, which simply counts something
loop .... >>
Agreed, do we consider a database to contain only homogeneous records, does
it maintain separate internal tables for different record types, or does it
do what some OODBMS' do and store a collection of heterogeneous records
which share a small common core allowing it to navigate and identify records
of various types. In that scenario, reading all the records in a "table" is
actually more like a query to find records by type (and a record may exist
in multiple "extents" when you consider an inheritance model).