Power Platform Community Forum Thread Details

Hi All,

I have text input in my screen which shows number of openings available for users to register for an event. Number of openings gets decremented by 1, when user registers successfully.

Text Input Default

If(Value(glbCurrentRecord1.'No of Openings Available')>0, glbCurrentRecord1.'No of Openings Available'&" openings left","Fully Occupied")

Patch formula when submit button is clicked

Set(
varPatchRecord,
Patch(
'Datasource',
glbCurrentRecord1,
{'No of Openings Available': Value(glbCurrentRecord1.'No of Openings Available') - 1}
)
);

Set(
glbCurrentRecord1,
varPatchRecord
);

The problem now is if number of openings left is 1, and if multiple users access the powerapp screen at the same time and register for an event, both users are able to register it successfully, which should not be the case.

How should I deal with this scenario? Any inputs would be helpful.

NOTE: Please take note that I am not using any form. Just placed controls in the screen and patching based on button click.

Categories:

Building Power Apps

Hi @Iantaylor2050 ,

Firstly, a fundamental flaw here is setting a Variable for a record that can "linger" in a User's App for an indeterminate amount of time and then relying on the Variable as being current. The Variable itself is a Record where the unique identifier (I have assumed you are using SharePoint here and used the ID) will always be correct, but any other values can be changed by another user between the time the record is opened and updated. I have consolidated two Variables here, but the main aim is to confirm the current state of the record immediately before it is Patched.

With(
 {
 wRecord:
 LookUp(
 DataSource,
 ID = glbCurrentRecord1.ID
 )
 },
 Set(
 glbCurrentRecord1,
 Patch(
 'Datasource',
 {ID: glbCurrentRecord1.ID},
 {'No of Openings Available': wRecord.'No of Openings Available' - 1}
 )
 )
);

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