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

• id
  Primary key of the em_history table.
  int(10) | unsigned | auto increment | primary key| indexed
  
• cid
  System ID of the customer in which the email was sent to.
  int(10) | unsigned | indexed
• batch_id
  Serial number of the email batch the email was sent with. Each email blast or autoresponder recieve a unique batch_id for historical reference.
  int(10) | unsigned | indexed
  
• template_id
  System ID number of the email template used in this email.
  int(10) | unsigned | indexed
• series_step_id
  System ID number of the email series step. This is used to display which step the modular mailer email is in the sequence.
  int(10) | unsigned | indexed
• send_date
  Date the email was sent.
  int(10) | unsigned | indexed | timestamp
  
• num_opens
  Number of times the specific email was opened.
  int(10) | unsigned | indexed
• open_date
  Date the email was opened by the recipient.
  int(10) | unsigned | indexed | timestamp
• bounce_date
  Date the email was bounced by the recipient, if applicable.
  int(10) | unsigned | indexed | timestamp
• recip_email
  Email address of the recipient who received the email.
  varchar(255)
• from_email
  Email address the email was sent from.
  varchar(255)
• from_name
  Name of the person who sent the email.
  varchar(255)
• bcc_email
  Email address that was BCC'd on the email.
  varchar(255)
• email_subject
  Subject of the email that was sent.
  varchar(255)
• text_msg
  Contents of the email (Text Format).
  longtext
• html_msg
  Contents of the email (HTML Format), the HTML within the email contents will be rendered when viewed in the administration area.
  longtext