Why is this an issue?
Overriding or shadowing a variable declared in an outer scope can strongly impact the readability, and therefore the maintainability, of a piece of
code. Further, it could lead maintainers to introduce bugs because they think they’re using one variable but are really using another.
Noncompliant code example
SET SERVEROUTPUT ON
DECLARE
foo VARCHAR2(42) := 'foo';
BEGIN
DECLARE
foo VARCHAR2(42) := 'bar'; -- Noncompliant - this variable hides the one above and should be renamed
BEGIN
DBMS_OUTPUT.PUT_LINE(foo); -- Displays "bar", which is confusing
END;
DBMS_OUTPUT.PUT_LINE(foo); -- Displays "foo"
END;
/
Compliant solution
SET SERVEROUTPUT ON
DECLARE
foo VARCHAR2(42) := 'foo';
BEGIN
DECLARE
bar VARCHAR2(42) := 'bar'; -- Compliant
BEGIN
DBMS_OUTPUT.PUT_LINE(bar); -- Displays "bar"
END;
DBMS_OUTPUT.PUT_LINE(foo); -- Displays "foo"
END;
/
