Exception handlers in Oracle’s PL/SQL programming language are essential for gracefully managing errors and exceptions that can occur during the execution of database code. They allow developers to handle unexpected situations, provide meaningful error messages, and maintain the reliability and robustness of database applications. Here’s a brief description of Oracle exception handlers:

1. Types of Exceptions:
   • Oracle PL/SQL provides predefined exceptions, which are common errors that can occur during database operations. Examples include NO_DATA_FOUND (when a SELECT query returns no rows) and TOO_MANY_ROWS (when a query returns multiple rows in a context where only one is expected).
2. User-Defined Exceptions:
   • Developers can define their custom exceptions to handle application-specific errors. This allows for more granular error handling and tailored error messages.
3. Exception Handling Constructs:
   • The primary constructs for exception handling in PL/SQL are BEGIN, EXCEPTION, and END. You wrap your code in a BEGIN block, and if an exception occurs, the program transfers control to the EXCEPTION block.
   BEGIN -- PL/SQL code here EXCEPTION -- Exception handling code here END;
4. RAISE Statement:
   • The RAISE statement is used to explicitly raise exceptions when certain conditions are met. This allows you to handle errors and exceptional cases in a controlled manner within your code.
   IF condition THEN RAISE custom_exception; END IF;
5. Exception Propagation:
   • PL/SQL allows exceptions to propagate up the call stack. If an exception is not handled within a block, it can be caught and processed by an enclosing block or the calling program.
6. Handling Multiple Exceptions:
   • You can handle multiple exceptions by listing them in separate EXCEPTION sections or by using the WHEN clause within a single EXCEPTION section.
   EXCEPTION WHEN exception1 THEN -- Handle exception1 WHEN exception2 THEN -- Handle exception2
7. Logging and Error Messages:
   • Exception handlers are often used to log error details to tables or files and to return meaningful error messages to users or application logs. This helps in diagnosing and resolving issues.
8. Nested Exception Handlers:
   • PL/SQL allows for nested exception handlers, where you can handle exceptions at different levels of your program. This is particularly useful in complex applications where exceptions may need to be handled at various levels of abstraction.

Exception handlers in Oracle PL/SQL are a critical component of robust database applications. They help in preventing unhandled errors from crashing the application, provide information for debugging, and offer a way to gracefully handle and recover from exceptional situations. Properly implemented exception handling enhances the overall reliability and usability of Oracle database systems.