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

• id
  Primary Key of the table.
  int(10) | unsigned | auto increment | primary key | indexed
• display_order
  Determines the order in which the field is listed on-screen during the checkout process and in the admin area.
  int(10) | unsigned | indexed
  
• title
  Descriptive title of the field. This will be displayed with the field in any form in which the field is included.
  varchar(255)
• description
  Description of the field. This will be displayed with the field in any form in which the field is included. It is a good place to include instructions.
  varchar(255)
• input_type
  The type of field, typically: text, dropdown, list_single, list_multi, radio. ("text_single" and "text_multi" will no longer need to be specified by the user. These are replaced by the "text" option. If a text field is set to have more than 1 line, the system will automatically change it to a "text_multi" field when it is displayed on a web page.)
  varchar(255)
  
• notes
  Information about the field. Only viewable within the administration area.
  text
  
• active
  The field's active status. Inactive fields are not displayed on any page that they otherwise would be.
  int(10) | unsigned | Values: 0/timestamp | Default: 1 | indexed
• is_unique
  Whether or not the value of the field must be unique. If greater than zero, then no other entry for this same field will be allowed to have the same value.
  int(10) | unsigned | Values: 0/timestamp | Default: 0
• num_lines
  The number of lines that a multi-line text field will contain. Only applicable if the type is a text field. If set to "1", then the text field will automatically display it as a single-line "text" input field instead of a multi-line "textarea" input field.
  int(10) | unsigned
• required
  Whether or not the field may be left blank or be submitted with an empty value.
  int(10) | unsigned | Values: 0/timestamp | Default: 0
• strict
  If the field's value is greater than zero, then only letters, numbers and underscores will be allowed in the value of the submitted field.
  int(10) | unsigned | Values: 0/timestamp | Default: 0
• encrypt
  If set to a value greater than zero, then the value of the submitted field will be encrypted prior to being saved in the database. Note that encrypted fields cannot be searched by the search tools in the administration or storefront areas.
  int(10) | unsigned | Values: 0/timestamp | Default: 0
• internal_only
  If set to a value greater than zero, then the value of the submitted field will not be displayed outside of the store's Administration area.
  int(10) | unsigned | Values: 0/timestamp | Default: 0 | indexed
• include_in_email
  If set to a value greater than zero, then the value of the submitted field will be included in any email correspondence generated by the software that includes information about the customer account.
  int(10) | unsigned | Values: 0/timestamp | Default: 0 | indexed
  
• maxlength
  Determines the maximum number of characters that may be entered into single-line text fields.
  int(10) | unsigned