Oracle9i™ Development by Example

Error Handling in PL/SQL

As defined earlier in this chapter, exceptions are errors or flags in PL/SQL. Exceptions are a way of gracefully handling certain conditions within the PL/SQL block, such as “no records returned from the SQL query” or “last record returned from the SQL query.” Other exceptions can be syntax errors in the PL/SQL code itself or errors returned from Oracle9i.

The syntax for exception handling, illustrated in Listing 3.2, is optional. If the exception area of the PL/SQL block is not handled, then it is propagated to the calling routine. For example, the SHOW ERRORS command in SQL*Plus is used to show any errors from PL/SQL that were not handled by the PL/SQL block. The exception syntax is

Listing 3.2. PL/SQL Exception Handling ...