Thank you Larry and Ed.

For the time being I won't use candidate keys because of needed 2.6 compatibility, but thank you for the information.

Larry, in regards to CusCKCheck, am planning to subclass it to use defaults if some properties are undefined:

Namely, it will use toForm.icMainAlias and toControl.ControlSource for icDBTable and icCKField. However, I am stumped about what to use for THIS.icPKAliasField and THIS.icPKFieldExpression since there is no primary key in table.

BTW, VMP is an absolutely incredible product! I had been stuck literally for years trying to use VFP and now, voila!

Thank you for your help and please thank Drew.

Alex