I've got a table in an Oracle `11gR2` database that contains five sequential fields, like `Field1`, `Field2`, `Field3`, `Field4`, and `Field5`. 

These fields are related:

* If `Field2` is populated, `Field1` has to be populated.
* If `Field5` is populated, **all** Fieldn fields should be populated.

What is the best way to validate that these fields are populated correctly? 

For instance, the query should return cases where Field3 is populated, but Field1 and Field2 are not. Or when just Field4 is populated. Or when Field1 and Field3 are populated. Etc. I'd like to avoid 25 different conditions in my filter if possible. 

Any help would be appreciated.