OpenEuphoria

RE: EDS Database indexing?

• Posted by gertie at ad-tek.net Jun 05, 2001
• 398 views

On 5 Jun 2001, at 22:26, Bernie Ryan wrote:


> 
> 
> Euman wrote:
> > Hello all,
> > 
> > I need to make some changes to an EDS database
> > and need some advise.
> > 
> > Lets take an example:
> > If I have 8000 records and a user decides to delete record # 6999
> > should I leave the key alone and nullify the record space
> 
>   I would suggest the following.
>   If the record #'s were a double-linked-list stored in memory then
>   all you have to do is move pointers when you delete a record. Then
>   when the file is closed this list would be written with the data
>   to the file. A Utility program or routine would be executed by the
>   user to clean the file at his option ( making a backup as it
>   runs ). Even if the record list gets destroyed in memory the
>   record's data is still there and can be recovered.

I agree wholeheartedly, never erase a database you make a change to! Instead,
rewrite
changes to a new name, use flush(), and then *byte verify* the new file, *then*
rename
the old file. Then be paranoid and verify the old file is renamed properly! A
minute spent
in automated verification can save you a week in doing manual data recovery.
Back
before i bought a battery-powered UPS here, the puter power would go out several
times a day, at random times, for up to an hour, so believe me, while the data
on the
*harddrive* is saf*est*, verify it anyhow! Don't trust floppies, ever! And
*never* use the
recovery option in windoze's scandisk or chkdisk,, they *will* trash the file at
the point
you least expect it and can least afford it.

<ramble mode on> (you thought it was already on?)

Btw, "here" = Alabama, usa. The electricity delivery system got somewhat better
after
the ice storm of 1993(?) left us without power for 10 days and Georgia Power
came in
to fix the lines. Since then, Alabama Power has had time to screw up the system 
again, and the UPS beeping is nearly a daily event again. How bad is it? Well, i
have
10 hrs of battery reserve, and then the baby gasoline-powered generator kicks in
to
recharge the battery. I am working on solar power tho, i hate that essentially i
am
paying a ethics-deprived power company to pollute my air to generate electricity
for
me, when it's possible i can do it myself cleaner and freeer (freer? free-r?
free'r?). )

Kat