Contains one entry for each attachment. The actual attachments contents are stored in a dedicated table: attachment_contents.
Structure of attachments
Unique internal identifier for the attachment.
The internal unique ID of the mail message to which the attachment belongs.
The mime type of the attachment such as 'image/jpeg', 'text/plain', 'message/rfc822'...
The attachment's size in bytes.
The attachment's filename, if present.
The character set for text contents (when content_type starts with 'text/'). Typical values are 'utf-8', 'iso-8859-1', 'us-ascii', ...
A string identifying the MIME part's content_id for the attachment. Other attachments may refer to this ID. For example HTML parts use <img src="cid:content_id_of_part"> to embed an attached picture. The use and syntax of content-ID is described in RFC 2392.
Tables referencing attachment_contents via Foreign Key Constraints