anchor.diff:  
   alter_authorization
       : alter_authorization_start (class_type colon_colon)? entity=entity_name entity_to authorization_grantee
  -    ; 
  +    ;
   
   authorization_grantee
       : principal_name=id
  
positive.code:     : SCHEMA
      | OBJECT
      ;
    
  class_type_for_parallel_dw
      : DATABASE
      | SCHEMA
  
negative.code: 
  alter_server_role_pdw
      : ALTER SERVER ROLE server_role_name=id (ADD|DROP) MEMBER login=id
      ;
  
  // https://docs.microsoft.com/en-us/sql/t-sql/statements/alter-service-transact-sql
  alter_service
  