Fix #44 - Created rule G-4260: Avoid inverting boolean conditions.

Author: kibeha

docs/4-language-usage/4-control-structures/2-case-if-decode-nvl-nvl2-coalesce/g-4260.md

@@ -0,0 +1,34 @@
+# G-4260: Avoid inverting boolean conditions.
+
+!!! tip "Minor"
+    Maintainability, Testability
+
+## Reason
+
+It is more readable to use the opposite comparison operator instead of inverting the comparison with `not`.
+
+## Example (bad)
+
+``` sql
+declare
+   l_color varchar2(7 char);
+begin
+   if not l_color != constants_up.co_red then
+      my_package.do_red();
+   end if;
+end;
+/
+```
+
+## Example (good)
+
+``` sql
+declare
+   l_color types_up.color_code_type;
+begin
+   if l_color = constants_up.co_red then
+      my_package.do_red();
+   end if;
+end;
+/
+```