This article outlines the database structure for the MMv4 ship_method_zone database table.

• id
  Primary Key of the table.
  int(10)| unsigned | auto increment | primary key | indexed
• object_id
  The system ID number of the shipping method.
  int(10) | unsigned | indexed
• zone_type
  The type of zone:  S = state, C = country, Z = zip code
  char(1) | Values: S/C/Z | Default = Z | indexed
  
• zone
  The string of the zone:  The ISO code for state or country, or the zip code.
  varchar(255) | indexed