host: author title address host port username password encryption
campaign: _host author title description time reply-to
subscriber: _campaign address signup-time confirmed
attribute: _campaign title
attribute-value: _attribute _subscriber value
mail: _campaign title subject body
mail-receipt: _mail _subscriber time
mail-log: _mail _subscriber time
mail-queue: _host _subscriber _mail time
mail-trigger: _mail _receipt-to-mail? _receipt-to-link? time-offset
mail-trigger-tags: _mail-trigger _tag inverted
tag: _campaign title description
tag-table: _tag _subscriber
tag-trigger: _tag _receipt-to-mail? _receipt-to-link? time-offset
tag-trigger-tags: _tag-trigger _tag inverted
link: _campaign _mail title url
link-receipt: _link _subscriber time
