Have two tables with checksums,
If the checksum are equal, created the third.
Hmmm , if I don't have three, one for validation How would I determine which is correct.

The checksum scheme is based on only using data with a good checksum. This is ok if you can live with one of 256 failures not being detected.

Even with 3 writes, a checksum should be used just, in this case you need "belt, suspenders and a piece of rope".

Erik


Erik