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TN Hist271 Resolving the NULL value problem after upgrading the Wonderware Historian




This article from InSource shows how to resolve NULL value issues after you've upgraded from a lower version of the Wonderware Historian and you are no longer able to see previously stored data in the old history blocks and instead receive NULL values.  This is caused by the fact that the older Wonderware Historian used another storage method and and the AIHistory table needs to updated. Re 

  • Author: Rufus Handsome
  • Published: 04/18/2017
  • Applies to: Wonderware Historian 2014 and 2014R2


To resolve the NULL value issues, follow the below steps.

Step 1 - Backup the runtime database using the MS SQL Server Management Studio 

Step 2 - Disable & Shutdown Historian using the SMC

Step 3 - Run the SQL script below against the Runtime database using MS SQL Server Management Studio

 '*********** BEGIN SQL SCRIPT ***************'

 Use Runtime


Update Runtime..Tag

Set AIHistory = 1

Where TagType != 7

And TagName  not like ‘Sys%’

 '*********** END SQL SCRIPT **************'

 Step 4 - Re-Enable and Restart Historian using the SMC

 Step 5 - Check to see if you have data using the Historian Client Trend or Query tool.