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

• order_id
  Reference to the order's SID number: orders.id.
  int(10) | unsigned | indexed
• tax_id
  Reference to the tax's SID number: tax.id.
  int(10) | unsigned | indexed
• tax_value
  Displays the amount of tax was applied to this order for this tax.id
  double(16,2) | unsigned | indexed
• zone_type
  Reference to the tax_zone.zone_type
  char(1) | values: C, S, Z | indexed