Re: BLOBs, MySQL, hex. Oh my
Re: BLOBs, MySQL, hex. Oh my
- Subject: Re: BLOBs, MySQL, hex. Oh my
- From: Serge Cohen <email@hidden>
- Date: Thu, 8 May 2008 15:01:37 +0200
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Hello;
One thing I don't understand, is that in MCPKit, you're supposed to
"prepare" (that is hexcode) the BLOB when you perform the INSERT, but
when using a query and fetch a row, the column containing a BLOB
should already be returned as NSData... This NSData should represent
the exact binary replicate of the INSERTED NSData (before it was hex-
coded) ...
In other words, to my knowledge one would need to use the -
[MCPConnection prepareBinaryData:] method at the time of the insert,
but there should be NO need to any back conversion when getting the
result of a QUERY.
Is there something I'm missing here ? (unless you are indeed storing
your BLOB as a TEXT, in which case MySQL would store the hex-coded
text rather than the binary represented by it, and in which case it
would return the TEXT which you would have to UN-hexcode yourself ...
if this is the case, then the problem lies in the table definition,
you "just" have to make sure to declare the column as BLOB rather than
TEXT, right ?)
Serge.
Le 8 mai 08 à 02:16, Ben Einstein a écrit :
Hi All,
I have an enterprise DB application that once used DO to move some
files around (images and zip files, mostly). After some serious
testing and lots of reading, I decided to move this to a few
different BLOB fields in the database. Despite major warnings from
people, I've found that images work great (specifically, NSData/
NSImage). I can notice a very minor speed drop a few milliseconds,
but being able to drop DO and it's woes is completely worth it.
Unfortunately, I didn't quite test the zip files, figuring it would
be the same. I'm using Serge Cohen's MCPKit (aka SMySQL), which has
a nifty little function to convert NSData to a MySQL-legal NSString.
On the other end, someone on the Apple list posted a few lines of
code to bump returned data into it's original NSData object. With
the zip files (no larger then 600kb) that method takes 30 - 40
seconds to run. On an image of a similar size, it takes 0.1 seconds
on a slow day.
Does anyone know why this would be? Is there an easy way to get
around this? I suppose my understating of hex is lacking, but I
always thought a hex string was a hex string was a hex string;
length was all that mattered.
Thanks,
Ben Einstein
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.8 (Darwin)
iEYEARECAAYFAkgi+Y0ACgkQlz6UVQtc2uw04wCfR77KlokLWAk533hza8gF3WqQ
X4EAoOMlMyytSQdFArPkOZ+uITE9OtI5
=aw++
-----END PGP SIGNATURE-----
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden