ExternalUser field in Sitecore DMS Visitors table

Question

My site is hosted in Sitecore 7.2 and we are using DMS for analytics. I tried to fetch count details based on user email who access a particular item which is restricted for one particular group. I got some users which are not belongs to the group. While investigate I found the below steps(I am not sure).

SELECT distinct ExternalUser,COUNT(distinct [Pages].visitid),[Pages].visitid
  FROM [Analytics].[dbo].[Pages]
  inner join [Analytics].[dbo].Visits on Pages.VisitID = Visits.Visitid and Visits.startdatetime >'10/11/2016'
  inner join [Analytics].[dbo].Visitors on Visitors.VisitorID = Visits.Visitorid
  where ItemID = 'Some Item ID' and 
  Visits.[VisitorId] in (SELECT VisitorId
  FROM [Analytics].[dbo].[Visitors]
  )
  group by ExternalUser,[Pages].visitid

1. User logins with the credentials for which the particular page is denied.
2. Visitors table gets updated with this details.
3. Then users logs out and logs in with the email address to which the access is available.
4. Now user can access the page.
5. However the externaluser field is not getting updated in Visitors table.

Can anyone let me know if my understanding is correct or not.

Answer 1

it seems that your scenario is occurring when two different users (with different permissions) are sharing the same device to login on the website.

This blog on the Sitecore Community site describes how DMS stores visitor records: https://community.sitecore.net/technical_blogs/b/damian_brooks/posts/dms-recognising-users-across-devices

As the blog suggests for a different scenario (same user browsing a website on two different devices), I think you need to identify the VisitorId of the user that is logging in and refresh the VisitorId cookie in the browser.