Before trapping all possible exceptions, it is best to try to trap the specific ones and try to recover from those.

== Noncompliant Code Example

----
SET SERVEROUTPUT ON

CREATE TABLE hitCounter
(
  page VARCHAR2(42),
  hits NUMBER,
  CONSTRAINT pk PRIMARY KEY (page)
);

CREATE PROCEDURE hitPage(pageIn VARCHAR2) AS
BEGIN
  INSERT INTO hitCounter VALUES (pageIn, 1);
EXCEPTION -- Noncompliant, the only exception handler is WHEN OTHERS
  WHEN OTHERS THEN
    IF SQLCODE = -1 THEN
      UPDATE hitCounter SET hits = hits + 1 WHERE page = pageIn;
    ELSE
      DBMS_OUTPUT.PUT_LINE('An unknown error occured!');
    END IF;
END;
/

BEGIN
  hitPage('index.html');
  hitPage('index.html');
END;
/

SELECT * FROM hitCounter;

DROP PROCEDURE hitPage;
DROP TABLE hitCounter;
----

== Compliant Solution

----
SET SERVEROUTPUT ON

CREATE TABLE hitCounter
(
  page VARCHAR2(42),
  hits NUMBER,
  CONSTRAINT pk PRIMARY KEY (page)
);

CREATE PROCEDURE hitPage(pageIn VARCHAR2) AS
BEGIN
  INSERT INTO hitCounter VALUES (pageIn, 1);
EXCEPTION
  WHEN DUP_VAL_ON_INDEX THEN
    UPDATE hitCounter SET hits = hits + 1 WHERE page = pageIn;
  WHEN OTHERS THEN
    DBMS_OUTPUT.PUT_LINE('An unknown error occured!');
END;
/

BEGIN
  hitPage('index.html');
  hitPage('index.html');
END;
/

SELECT * FROM hitCounter;

DROP PROCEDURE hitPage;
DROP TABLE hitCounter;
----

include::../see.adoc[]