(PHP-DB folks, ignore this top question - unless you want to answer)
Which type of DB/Table provides table locking while a process is
altering data? I don't care for locking while using SELECTs, but I do
need locking when something's being INSERTed or UPDATEd, so I won't get
two processes trying to do the same darned thing at the same time.
(MySQL folks, ignore this bottom question - unless you want to
answer)
I'm somewhat lost on how to do the following:
I'm trying to go through a table and check for a particular
information. If it doesn't exist, then go ahead and issue an INSERT
with the relevant data. The next time another process comes along,
it'll obviously find the information and issue an UPDATE instead. But,
what happens if I get two processes running at the same time, trying to
find information that does not exist yet?
If both issue a SELECT and find the information not there, both will
try to issue an INSERT, where really I want one of those processes to
wait for the first one to finish doing whatever it needs to do, prior to
continuing. (all of this is being done in PHP by the way). Does anyone
have any suggestions for this scenario (or am I just blowing smoke out
my arse and there's something else, internally, that I'm not aware of?)
When (and how) to issue some sort of "wait" state for one process while
the other's finishing what it needs to do, then restart the second
process (which should re-check for existing information, and not blindly
issue another INSERT right after the first one).
--
W | I haven't lost my mind; it's backed up on tape somewhere.
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Ashley M. Kirchner <mailto:[EMAIL PROTECTED]> . 303.442.6410 x130
IT Director / SysAdmin / WebSmith . 800.441.3873 x130
Photo Craft Laboratories, Inc. . 3550 Arapahoe Ave. #6
http://www.pcraft.com ..... . . . Boulder, CO 80303, U.S.A.
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