I understand that there is a global reset button for synching the column comments with the attribute definitions. However, I do not see any such button for synching the attribute definitions with the column comments. How can that be done?
A button does not exist for synching attribute definitions with column comments because the hierarchy is from logical to physical. However, here is a way to do that:
Launch the Bulk Editor Wizard. Select Column under the Object Types, Comment, and Definition boxes under the Property Types, and select the column you want - or the box if you want all columns under the Object Instances. Save the result set as a CSV file by clicking the save icon in the top menu. Open the csv file in Excel, move the comments into the definition side, and then import that into your model using the Bulk Editor.