>>5: UNIQUE indexes, not only are they misused but they could easily be totally removed from the product without any alteration in capabilities.
>
>I have never understood these and have avoided them.


I have never used a UNIQUE index in an application, but I find them useful at the command line. For example, I want to know all of the different codes that have been used in field RESERV.cPayer:

index on cPayer to TEMP unique
list cPayer


Peter Robinson