Patch within ForAll with LookUp with Field = ThisRecord.Field issue

(0) Share

Report

Posted on by BrianHFASPS

732

I have this code:

Patch(
 'Student List',
 LookUp('Student List', 'User ID' = ThisRecord.'User ID'),
 {Carnet: LookUp('Student List','User ID' = ThisRecord.'User ID',Carnet) - 1}
)

I think the issue is the 'User ID' = ThisRecord.'User ID' as it always returns the first record in the table. In other cases I usually make sure the field names aren't the same in the collection / table that the ForAll is processing on but in this case I didn't and it would be cumbersome to fix. Before copying the column to another named column I wanted to see if there was something I was missing.

Categories:

Building Power Apps

I have the same question (0)

All responses (3)

Answers (1)

Sort by

RandyHayes 76,299 Super User 2024 Season 1 on at

Like
a
(1)

Report
Copy link

Link copied!

@BrianHFASPS

Your formula (Lookup) will only return the first record. ThisRecord is going to refer to the Student List record. And, that will always be equal for each record, so the first will only be returned.

What is it that you are trying to do in this formula?

What are you trying to look up?

Was this reply helpful? Yes No
Verified answer

BrianHFASPS 732 on at

Like
a
(0)

Report
Copy link

Link copied!
I thought ThisRecord would return the row off the currently being acted upon ForAll loop, I guess not.
I did this:
Collect(TempAttRoster,(RenameColumns(Roster,"User_x0020_ID","TempID")));
After which my code becomes:
Patch( 'Student List', LookUp('Student List', 'User ID' = TempID), {Carnet: LookUp('Student List','User ID' = TempID) - 1} )
It shouldn't cause issues now. I have a collection of students and I am doing processing on that list. It is just that the column name in the collection is the same as the table I am trying to patch and causes a circular reference. In most cases I was careful to name the unique ID column different in tables or collections and I just goofed on this one and tried to take a shortcut.

Was this reply helpful? Yes No
RandyHayes 76,299 Super User 2024 Season 1 on at

Like
a
(2)

Report
Copy link

Link copied!
@BrianHFASPS

If you are using that Patch IN a ForAll, you are using is backwards and are trying to use it like a ForLoop in some development language - which PowerApps is not. ForAll is a function that returns a table of records based on your iteration table and record schema.

It is more efficient to use the function as intended and will provide better performance especially when Patching. This will present the more horrific performance of all.

Construct should be:

Patch(yourDataSource, ForAll(.... )

If you are using:

ForAll(... Patch(...

It is backwards and going to kill your performance!

Then you can use As to name your ForAll values for use in your Lookup.

i.e.

Patch('Student List', ForAll(yourTable As _item, With(LookUp('Student List', 'User ID' = _item.'User ID'), {ID: ID, Carnet: Carnet - 1 } ) ) )

Was this reply helpful? Yes No