SQL Developer Data Modeller and Data Dictionary question
The data dictionary will only show what it can.

Users can design their schema with or without referential integrity defined in the actual database.

When you import a data dictionary, using SQL Developer, to a new or existing relational data model, the foreign key constraints will be shown by default - if they are there to begin with.

Now, specific to the tool, it CAN attemp to infer any relationships. It does this by looking for common column names sprinkled around your tables, like an 'XYZ_ID' column, that happens to be a PRIMARY KEY in a driving table.



I have step-by-step instructions for this here, on my blog.