How to validate dates in OCL expressions.
Bold allows the model to specify a list of constraints in OCL (Object Constraint Language). The problem that I encountered was that OCL didn't understand a simple expression such as "startDate <= endDate" which is what I am used to doing in Delphi.
The solution is to cast the date as a "float" value. The following expression works perfectly.
startDate.DateTimeAsFloat <= endDate.DateTimeAsFloat
Information provided by Eric Holton on the Bold news groups, thanks Eric!.