To start a Logical Model you can right click over the "Logical Model" entry in the Browser tree and select Show from drop-down menu. This will display an empty Logical Model diagram. You can then select the "New Entity" button from the button bar below the main menu, and click over the diagram to add an Entity there.
Similarly, to start a Relational Model you can right click over the "Relational_1" entry in the Browser tree and select Show, and then then select the "New Table" button to srart adding Tables to the Relational Model diagram.
Alternatively you can start by using Import/Data Dictionary from the File menu to import an existing database definition.
Dimitar gave some documentation references in a recent message in this forum Re: SQL DATAMODELER DOCUMENTATION?
There are also some links on the "Start Page" that appears when you first use Data Modeler. (To reopen this select "Start Page" from the Help menu.)
Creating your first models
The Data Modeler browser starts with empty Logical and Relational models. This allows you to start a new design and build a model from scratch, whether a logical model with entities and attributes, or a relational model with tables and columns. The Data Modeler also supports metadata to be imported from a variety of sources, which include:
* Importing metadata from:
o DDL scripts
o Data dictionary
* Importing from other modeling tools:
o Oracle Designer
o CA Erwin 4.x
* Importing other formats:
o VAR file
o XMLA (Microsoft, Hyperion)
Once you have created and saved your models, you can open these or share them with colleagues. To open an existing model, use the menu:
* File | Open—browse to the location of the files, which then opens the full design with all of the saved models
* File | Recent Designs—opens the full design, with all of the saved models, with no need to first search for the location
* File | Import | Data Modeler Design—more granular, offering a choice of models saved in a set of models
Use File | Recent Diagrams to display a list of all diagrams you have recently worked on and saved. Using this approach saves you from needing to browse to the location of the stored files.
Also you can see the following link: http://www.packtpub.com/article/introducing-sql-developer-data-modeler-part1 Mark the Answer correct or Helpful accordingly
Yes, that was a helpful answer. Now I have a follow-ups:
I did figure out how to change the colors and fonts for individual entity classes and relationships. Is there a place to set defaults?