MRAB wrote:
On 18/07/2012 03:19, Ethan Furman wrote:
MRAB wrote:
On 17/07/2012 23:57, Ethan Furman wrote:
In Foxpro if you do a
GOTO 7
with deleted off and record 7 is deleted, the record pointer doesn't
move (at least in version 6).
I don't like that.
I see four other options:
0) don't move the pointer (listed for completeness)
1) go to that record anyway
2) go to the next undeleted record
3) go to the seventh undeleted record (possibly the least practical)
4) raise an exception
Any opinions?
What happens when you 'delete' a record? Does it disappear immediately,
or is it merely marked for deletion?
Marked for deletion.
If it is marked for deletion, can it be unmarked? Will a marked record
be removed when the file is closed, or does the file need to be
explicitly purged/compacted?
Yes, it can be unmarked. No, the table must be explicitly packed.
If it is merely marked, then I think the best option is 1, or possibly
4 if the file is compacted when closed.
There is a use_deleted setting that controls whether deleted records are
accessed or skipped. Skipping is fine when looping, not so fine when
going directly to a particular record.
If use_deleted is false, does that mean that deleted records are
hidden, or just that when iterating through the records the deleted
ones aren't yielded?
Definitely the latter, but I'm starting to wonder if the former should
also be the case.
~Ethan~
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