The Repair Diagram tool of the Database Designer for PostgreSQL allows to check and repair underlying physical structure of model file (*.pdd) if some reference integrity was broken.
During file opening Database Designer automatically checks file for reference corruption, and if Repair needed Model Repairing dialog appears. You may Cancel this operation. However, it is strongly recommended to proceed. After Repairing you may use Save As dialog to leave a backup of old model file.
To open manually the Repair Diagram dialog select the Diagram | Repair Diagram menu item.
Check Color tables with duplicated IDs to distinguish entities with non unique identifiers.
Use the Fill Color drop-down list to select the desired color for such action.
Check Color references which are joined to tables with duplicated IDs to mark the references which can not be unambiguously related to single table.
Use the Fill Color drop-down list to select the desired color for such action.