A foreign key relationship is established between parent and child entities.
The Default Value of parent key is uniqueidentifier() value.
Toad Data Modeler places the same Default Value in child key.
Value of child key is removed; however, once any changes are made to the parent key, the same Default Value is again written to child key.
1. Select Settings | Options menu option
2. Under Model | Physical Model section, select General
3. On the right side, there will be an "Attribute Properties Propagation" drop down
4. Use down arrow icon here and select "Only Obligatory PK Properties" option
5. Hit OK to close Options screen
