title: Using "Required" property vs "Is Not Null" validation rule for an Access column
body: <p>I am making a database with queries, forms, reports and User Interfaces - but what i cannot seem to understand is; when in Design view of a table, what would be the difference between pressing Yes on Required or writing "is not null" as a Validation rule.
  Would i need to use both or can i use either one?
  I have tried looking online but i have not found an answer yet.</p>