How can I generate unique random CHAR(6) with values “AAAAAA” to “ZZZZZZ”?
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Informix (All version up to 10 years old):

CAVEAT: I'm not a sophisticated developer, as some of you already know, but maybe you could help me out with a rough design for this?

I would like to mimic the way airline reservation systems randomly generate unique record locators for their primary keys. None of the resulting values can form obscene words or other specified patterns, so a separate lookup table containing the prohibited values is required.

