Preventing more than one child record

AppSheet AppSheet Q&A
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1

I have a parent table for jobs we are working in a disaster response in North Carolina with one “job” per home. I have set up the ability to have child records for each job for different types of work (chainsaw, tear out, tarping, etc.). Each type has it’s own table. I only want ONE child record per type of work for each job (one chainsaw record, one tarp record, etc.). There’s not a good way to eliminate the “Add” button once a child record has been added. I’ve asked this forum before and the solutions don’t fit our needs. The users do need to be able to edit the existing record, but not add a second record. Is there a way to require a unique child record and one only?

Thanks for any help you can provide

Wick

2

Hi,

Valid If is commonly used to prevent duplicate values from occurring within a table
The following post may help you. One to one ddbb relationship
https://www.googlecloudcommunity.com/gc/AppSheet-Q-A/Forcing-one-to-one-database-relationships/m-p/335588#S108670

List expressions. “Use lists to validate column values” section
https://support.google.com/appsheet/answer/10107669

1 Like
3

I tried the technique using the following:

ISBLANK(
FILTER(
“Trees”,
([_THIS] = [Trees Job ID])
)

  • LIST([_THISROW])
    )

I should note that the “Trees Job ID” is a reference field inherited from the parent record and is not the key to the child table (Trees). I can edit existing child records just fine. When I try to add a child record, it adds, but when it syncs with the server, the Trees Job ID field is blanked out. The record is added to the Google Sheet table but has no value in that field, making it inoperable.

Thanks, Wick

4

After working with it a bit, I could make the Trees Job ID editable and the records stayed as they should. I updated the “Editable?” field so only the owner can edit that field and it still works well. Without the editability by someone, the records lost the Trees Job ID field result. Weird.

Wick