Emails in the inbox have two parts to them: an entry in the mailbox table (where the body of the email resides) and an entry in the cal table in order that it can appear on a user’s calendar/activity list.

The cal entry may or may not have an accountno, depending on whether or not the email is linked to a contact.

The two records are linked by mailbox.linkrecid = cal.recid

When an email is ‘deleted’ then the folder field in the mailbox record is changed to ‘x-gm-trash’ and, in cal, the record has its userid and accountno fields blanked out.

The deleted email is visible in the trash folder of the user’s email centre because the mailbox record has its own userid field. However, the cal record is now unlinked from both the user’s calendar and from the contact record.

When you restore an email out of the trash then the accountno (if any) and the userid are recreated in the cal record from the entries held in the corresponding mailbox record.

When an email is ‘filed’ or ‘fast-filed’ then the folder field in mailbox is changed to an internal reference that equates to one of the sub-folders under ‘filed’ in the email centre, with the folder2 field referring a further sub-folder if necessary (eg year then month). The cal record is deleted and a conthist record is created to take its place. The link is similar to the one before: mailbox.linkrecid = conthist.recid