Fix #45 - Created rule G-4270: Avoid comparing boolean values to boolean literals.

Author: kibeha

docs/4-language-usage/4-control-structures/2-case-if-decode-nvl-nvl2-coalesce/g-4270.md

@@ -0,0 +1,38 @@
+# G-4270: Avoid comparing boolean values to boolean literals.
+
+!!! tip "Minor"
+    Maintainability, Testability
+
+## Reason
+
+It is more readable to simply use the boolean value as a condition itself, rather than use a comparison condition comparing the boolean value to the literals `true` or `false`.
+
+## Example (bad)
+
+``` sql
+declare
+   l_string    varchar2(10 char) := '42';
+   l_is_valid  boolean;
+begin
+   l_is_valid := my_package.is_valid_number(l_string);
+   if l_is_valid = true then
+      my_package.convert_number(l_string);
+   end if;
+end;
+/
+```
+
+## Example (good)
+
+``` sql
+declare
+   l_string    varchar2(10 char) := '42';
+   l_is_valid  boolean;
+begin
+   l_is_valid := my_package.is_valid_number(l_string);
+   if l_is_valid then
+      my_package.convert_number(l_string);
+   end if;
+end;
+/
+```