How to Read a Diagram of Modeled Tables

Tables and foreign keys can be modeled on a database diagram in JDeveloper.

1. Tables

A modeled table contains information about the offline table definition, and the columns and constraints for that table.

2. Name Compartment

The name compartment contains the <<table>> stereotype, followed by the offline schema name and the name of the modeled table.

3. Columns Compartment

The columns compartment contains the column name, datatype, size and precision.

4. Constraints Compartment

The constraints compartment contains the name and type of the constraint.

5. and 6. Foreign Keys

This diagram shows some foreign keys. Optional foreign keys are shown with 0..1 at one end, and mandatory foreign keys are shown with 1.

The diamond shape at the end of the foreign key shows whether an On Delete rule has been set and what it has been set to. If the diamond is black then CASCADE has been chosen. If it is white then SET NULL has been chosen. If there is no diamond then the On Delete rule has not been set.

To draw a key, start with the owning table.