I have two lists MemberList and MemberCertsandQualsList. Both lists share several common columns:

Location Alpha

Location Name and No.

Location Region

Location County, etc...

I have a Patch in Power Apps that updates these fields in the MemberList. The update only has to change a single line of data in the MemberList, as each UnqID only appears once on that list.

I also need these same exact fields updated in the MemberCertsandQualsList every time they are changed/updated the MemberList. The process for updating the MemberCertsandQualsList may have to update multiple line items of the same information base on the UnqID depending on the number of certs or quals the member has in the system. The UnqID may appear several times in the MemberCertsandQualsList; consequently, the entire list (more than 5,000 items) would need to be check every time a members data is updated in the MemberList.

It is more prudent or of greater efficiency to use a Lookup (if such a thing is even possible) to pull the common fields into the

MemberCertsandQualsList, or to use a Flow to update the MemberCertsandQualsList every time there is an update of change to the MemberList?

2 Answers 2


Best practice is to avoid duplicating information if possible, so if these two lists are in a one-to-many relationship, I think, you could use Lookup column to show information from the MemberList to MemberCertsandQualsList. Besides, Flow license has limitation as to how many actions you could run in 24 hours, and that can be used to some other tasks.

Please see this post showing how to link lists using lookup columns.

  • What triggers population of the Lookup field in the gaining list. I created a Lookup column in the MemberCertsandQualsList and called it 'Park', The Park Lookup column is looking at the MemberList, Field Park. There is not data in the field.
    – Curtis
    Feb 10, 2021 at 20:08
  • While you're in MemberCerts and adding a new record or updating an existing record, do you see a dropdown option for column "Park"? If it's pointing to MemberList, it should show you options to choose from. The idea is that location fields just need to be updated at one place, but to be seen in both places by using a LookUp column. Feb 10, 2021 at 20:36

Flow is never the first option when it comes to “efficiency”, especially when you are dealing with a large list. A Lookup column is definitely the better option in this scenario, but you should mind you head with the 5000-item limit as well.

One more thing you should be aware if you want to build a flow. The trigger “When an item is created or modified” will be triggered by the flow itself if you use "Update Item" action within, you will need to find a way to prevent infinite loops so that the flow and your environment keeps working.

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