Front end - find sum selected of n:m attibutes before save

francis_mat

I have a requirement where on a form where I select n:m attributes and i have to populate the sum of the values selected into a form field before the form is save/submitted.

I have the following relations and relevant attributes
1) Facilites
-> id
-> name
-> rent
2) Bookings
-> id
-> rent (calulated - sum of selected facility rents)
3) Booked_Faclities
-> booking_id
-> facility_id

Is this possible? if so how?
Thanks in advance.

Cheers
Francis

gabriel

Yes it´s possible, but would take some steps. In short:

Whenever the n:m input changes, a frontend function would trigger.
The frontend function would collect the record IDs of the n:m input (app.get_field_value()) and would send them to a backend function.
The backend function would collect all the sums/values from the given records and do the required maths. It would then return the sum value.
The original frontend function would receive the return value and store it in another, possibly readonly field on the same form (app.set_field_value()).

francis_mat

gabriel

The frontend function would collect the record IDs of the n:m input and would send them to a backend function

How can I collect the record IDs?

gabriel

app.get_field_value() from the n:m input field gives you an array of the selected record IDs (or NULL if its empty).

francis_mat

gabriel

Thanks.

But how do I define a backend function that accepts an array of bigint? I tried type BigInt64Array, but I get an error, "Error: type BigInt64Arraydoes not exist...."

I tried
facility_ids bigint Array
and REI3 allowed to save the function .

Cheers
Francis

lsw-fabian

Try facility_ids bigint[] - this should work

francis_mat

lsw-fabian

Thanks Fabian

It worked

Cheers
Francis