Re: any support for deleting an entry from cdb file?

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Hi,

On Apr 11, 2005, at 8:24 PM, Dev Man wrote:

> Is there any way to delete records from the CDB database?
> I looked at the CDB source code a bit but didn't see offhand.
> If not, is it feasible to add?
> or is it really limited to add/read operations?

As you already know by now, 'C' is for constant: write once, read many.=20=

Neither deletes nor updates are available in the CDB library.

But :)

In an application I wrote, I needed to invalidade an entry of the CDB,=20=

to delete it. What I did, was this: each data element has an extra byte=20=

prefix, state. Initially the state is a space. If I want to delete it,=20=

I put a 'X' there.

I then made a wrapper around cdb_get that looks at the first byte and=20
if it's a space, just returns the size of the data - 1, if it's an X=20
returns 0.

Deleting is just opening for write, cdb_get, write an 'X'.

Update is possible, but even more hackish: if your update data is=20
smaller than the original data, and the key is the same, you could just=20=

write to the CDB, but the cdb_get would always return the original size=20=

of the data. You have to keep track of the real size of the data=20
inside. I did it once for proof of concept but I didn't use it.

Best regards,
--
Pedro Melo Cunha - <[email protected]>
Novis Telecom, S.A. - Dir. Rede - ISP <http://www.novis.pt/>
Edif=EDcio Novis - Estrada da Outurela, 118 - 2795-606 Carnaxide
tel: +351 21 0104340 - fax: +351 21 0104301


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