| Subject | Re: [firebird-support] Re: detect duplicate blobs, how to? |
|---|---|
| Author | Tim Ward |
| Post date | 2017-02-09T14:45:46Z |
You are aware of course that you can't
use any hashing function on its own to detect duplicates? - the
best you can do is detect *probable* duplicates, filtering out
ones that are *definitely* different, in order to *reduce*, not
eliminate, the amount of work you end up doing comparing byte by
byte.
On 09/02/2017 14:39, hamacker sirhamacker@... [firebird-support] wrote:
On 09/02/2017 14:39, hamacker sirhamacker@... [firebird-support] wrote:
Well, the man page says fully supports text BLOBs, I assume that binary not.If HASH() behavior will operate ^Z and others control chars in Blob Image, then now I need to think how to use this function to kill duplications.
Any function like CHECKSUM, CRC32,...?
2017-02-09 10:36 GMT-02:00 Dmitry Yemanov dimitr@... [firebird-support] <firebird-support@yahoogroups.com>:
09.02.2017 14:48, hamacker wrote:
>
> There is a HASH function but only for string.
It works for blobs as well.
Dmitry
-- Tim Ward