I am facing an issue mentioned in the above article. i.e. Enterprise Architect is not giving any error when I create a constraint on an attribute with wrong syntax.
The answer is simple: it fakes OCL. EA is doing no syntax check of OCL itself. In no way does it execute OCL and will not do any constraint checking. You can only mark a constraint as being OCL:
That's it. Just try to enter an inalid constraint and EA will swallow it with no warning.