Re: [CFCDev] Data Locking is it too hard?

[Ben Curtis]

2) in tbl_Versions, add a reference to "tbl_A," the rows selected, 
and the last modified date timestamp of each selected row

Instead of timestamp, consider a checksum/hash of the relevant values 
in the row which is easy to calculate in most dbs using builtin 
functions (eg MS-SQL has CHECKSUM() and BINARY_CHECKSUM() while MySQL 
has CRC32()). Store the hash in your web app and check the new hash 
for the row before an insert/update. Timestamps can be reset on 
purpose or accidentally -- a checksum is a lot cleaner (it's part of 
what MS-SQL uses under the hood for replication)

Slick!
Also has the advantage of providing a check for the incoming data to 
see if it really was changed at all.

--
        Ben Curtis
        WebSciences International
        http://www.websciences.org/
        v: (310) 478-6648
        f: (310) 235-2067

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