Object references are useful for uniquely identifying and locating an object. Within Oracle8i, a reference to an object within an object table may be obtained by using the REF pointer.
An object type may be declared as a reference (REF) to another object type.

When you have completed this module, you will be able to:

1. Describe the Structured Query Language (SQL) enhancements that allow you to query related object tables
2. Detect dangling references
3. Write a query using a DEREF data type to retrieve related data
4. Determine when PL/SQL is appropriate or required for querying object tables
5. Write a PL/SQL block to retrieve data from an object table

In the next lesson, we will begin describing the SQL enhancements that allow you to query related object tables.