anchor.diff:          -? +.selectStmtWithoutCTE
           -|> (|>)
   
  -let private foreignKeyRule =
  +let private foreignKeyRule = // Remove SQLite stuff? But support cascade and set null...
       let eventRule =
           %% kw "ON"
           -- +.[
  
positive.code: 
  let private notNullOperator =
      %[
          kw "NOTNULL"
          %% kw "NOT" -? kw "NULL" -|> ()
      ]
      |> withSource
  
negative.code: 
  
  let private foreignKeyDeferClause =
      let initially = // Remove SQLite stuff?
          %% kw "INITIALLY" -- +.[ %% kw "DEFERRED" -|> true; %% kw "IMMEDIATE" -|> false ] -|> id
      %% +.(zeroOrOne * kw "NOT")
      -? kw "DEFERRABLE"
  