Restrict deletion if referenced id is being used

[nlozano]

Hi, we were wondering if it's possible to restrict the deletion of a row in a table if the id for that row is currently being used by another table that references it, like it would if you set "on delete", "restrict" on a relational database (we're using BigQuery so it's not possible to set that restriction from the database itself). 

With the default behavior, if a row is deleted and another table references that id, it will still allow to delete it and the referenced record is untouched with an orphan referenced id. I see the "Is a part of?" basically would allow to do a "cascade" deletion, but that's not what we want. In the deletion behavior there's a "only if this condition is true" which might be the right way to do this, but we're not sure of what expression to use for it. Edit: Tried COUNT(REF_ROWS("table1", "refColumn")) = 0 and it hides the delete button for those that have referenced records, kind of works.

Thanks.

[dbaum · Accepted solution]

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@nlozano wrote:

Tried COUNT(REF_ROWS("table1", "refColumn")) = 0 and it hides the delete button for those that have referenced records

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Seems like a good approach. Besides not displaying the button to users, it actually disables the action altogether--e.g., if it's included in a grouped action. Do you think what you've done is insufficient for some reason?

[nlozano]

Thanks for the response. It's okay, it works fine like this. I just thought hiding the "delete" button without providing a reason why it's hidden could be unintuitive to users, but hopefully it won't be an issue as long as we explain it somewhere.

[Suvrutt_Gurjar]

Another simpler expression to try would be 

ISBLANK([Rev Ref Column in the parent table])