Flush/Delete question

[Ruslan Zasukhin]

On 6/30/05 4:21 PM, "Florian Bogeschdorfer" <fb at memedia.de> wrote:

> V4MD 1.1, Server/Client
> 
> Hi Ruslan!
> 
> This is basically a security question for me.
> If I change a record to a set of "x", flush the DB and then delete the
> record, the record will be deleted but physically it will remain in the Db
> file so that I could search for it with a text editor.
> That is why I overwrote all fields with "xxxxx..." before:
> 
> For i=1 to numberOfRecordsToDelete
>   overwriteRecord("x")
>   flush()
>   deleteRecord()
> next
> 
> If I do this with thousands of records, Valentina will crash finally. And it
> takes very long...
> 
> Now I wonder what would happen if I do no flush in between?
> That is:
> 
> For i=1 to numberOfRecordsToDelete
>   overwriteRecord("x")
>   deleteRecord()
> next
> flush
> 
> 
> Will it 
> 
> a) work as expected, that is records are first "x"ed out and then deleted
> (only "x" remains in the DB file) or

I think yes, because it will override info in the cache page, and later
cache page go to disk...
 
May be only glitch if you will delete all records of that page.

Well, in 2.0 we have almost done, such feature as

    EraseOnDelete flag for db

> b) not overwrite the record at all since it has been deleted (records stay
> readable in DB file)



-- 
Best regards,

Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc

Valentina - Joining Worlds of Information
http://www.paradigmasoft.com

[I feel the need: the need for speed]