Rule Definition
An empty catch block defeats the purpose of exceptions. When an exception occurs, nothing happens and the program fails for an unknown reason. The application can be in an unknown state that will affect subsequent processing. Since the reason for the issue (the exception type and potential embedded message) are ignored, it will require more time to fix the issue.

Remediation
The exception must be handled correctly according to its type.

Violation Code Sample

Microsoft SQL Server:
BEGIN TRY  
-- Generate divide-by-zero error. 
    SELECT 1/0 
END TRY 
BEGIN CATCH  
-- Non-compliant
END CATCH;

MySQL and MariaDB:
DECLARE CONTINUE HANDLER FOR SQLWARNING 
# Non-compliant 
BEGIN 
# empty block
END;

PostgreSQL:
BEGIN
    INSERT INTO db(a,b) VALUES (key, data);
        RETURN;
    EXCEPTION WHEN unique_violation THEN
    -- Do nothing, and loop to try the UPDATE again.
    NULL;
END;

Oracle:
DECLARE
    pe_ratio NUMBER(3,1);
    BEGIN
        BEGIN  ---------- sub-block begins
            SELECT 1 / NVL(null, 0) INTO pe_ratio FROM dual;
        EXCEPTION
          WHEN ZERO_DIVIDE THEN
            -- Compliant
            pe_ratio := 0;
        END;  ---------- sub-block ends
    EXCEPTION
        WHEN OTHERS THEN
            -- Non-Compliant
            NULL;
    END;

Fixed Code Sample

Microsoft SQL Server:
BEGIN TRY  
-- Generate divide-by-zero error. 
    SELECT 1/0 
END TRY 
BEGIN CATCH  
-- Compliant
 SELECT ERROR_NUMBER() AS ErrorNumber, ERROR_MESSAGE() AS ErrorMessage;
END CATCH; 

MySQL and MariaDB:
DECLARE CONTINUE HANDLER FOR SQLWARNING 
# Compliant
BEGIN 
# not an empty block
SET done = TRUE;
END;

PostgreSQL:
BEGIN
    INSERT INTO db(a,b) VALUES (key, data);
        RETURN;
    EXCEPTION WHEN unique_violation THEN
    RAISE NOTICE 'caught unique_violation ';
    RETURN;
END;

Oracle:
DECLARE
    pe_ratio NUMBER(3,1);
    BEGIN
        BEGIN  ---------- sub-block begins
            SELECT 1 / NVL(null, 0) INTO pe_ratio FROM dual;
        EXCEPTION
          WHEN ZERO_DIVIDE THEN
            -- Compliant
            pe_ratio := 0;
        END;  ---------- sub-block ends
    EXCEPTION
        WHEN OTHERS THEN
            NULL;
            -- Compliant
            pe_ratio := Null;
    END;

An insider's guide to writing robust, understandable, maintainable, state-of-the-art ABAP programs - Part 3 Andreas Blumenthal - Horst Keller http://www.javapractices.com/Topic16.cjp http://cwe.mitre.org/data/definitions/391.html