-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 10/05/06 18:54, Jean-Christophe Roux wrote: > Why would I set a bytea column (containing picures) as a primary > key? Because I want to be sure that the same image is inserted > only once (that requirement comes from a real project) and using > a primary key for that purpose makes sense to me. A hash function makes better sense. SHA-1 creates a 20 byte string that is the digest of the file. Almost perfect as a primary key. SHA-256 (so far!) guarantees uniqueness in 32 bytes. > Am I going to > retrieve an image row by its image data? I would certainly like! > For instance, I would like to get the pictures whose main color > is green (requirement from a real project), and a select * from > images where main_color(image) = 'green' would be nice. That would speedily be handled by preprocessing metadata records as the image is inserted. - -- Ron Johnson, Jr. Jefferson LA USA Is "common sense" really valid? For example, it is "common sense" to white-power racists that whites are superior to blacks, and that those with brown skins are mud people. However, that "common sense" is obviously wrong. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (GNU/Linux) iD8DBQFFJql5S9HxQb37XmcRAgYjAKCeTur3N/AUwQLI79GYbde8nCMYwACfejg+ Xe3qGl7GHlhC4jssvGkAJ6w= =dW03 -----END PGP SIGNATURE-----
