I removed a check constraint from a table in my model. Then wanted to Synchronize data dictionary. The Compare models-dialog sees the difference but as I check the To drop-box (which is unchecked by default) and click DDL Preview the Preview is empty. I mean it’s totally empty, not even the standard ddl-comments like
-- Generated by Oracle SQL Developer Data Modeler 188.8.131.526
show up! Therefore I assume this behaviour to be a bug.
Thanks for reporting this problem. I have logged a bug on it.
Note that this problem does not occur for Check Constraints defined as part of the definition of a Column. It only occurs for Check Constraints defined at the Table level.