Update record for the Link to another record field

You want the linking to happen only when a new row is created? An automation would be a better way to go instead of pushing buttons indefinitely.

Especially since it doesn’t sound like you’re doing that much interlinking right now, so using up your monthly quota shouldn’t be a concern. But if that’s not the case, you should reconsider your approach outlined above; updating a single record at a time takes forever, and from what I’ve gathered, you don’t already have a way to glean record ids across different tables?

As for the code you’ve posted, we can do imperative programming more efficiently by declaring a temporary array above that for… of loop of yours, then instead of updating each record as we go along, we’d do something like

//create what you need to do the prepwork;
//a simple array would do in this instance, let's call it 'cache'
    let cache = []
    let am_id = record.getCellValueAsString("unique-id-am")
    let am_quota = record.getCellValue("AM Quota")
    if (!am_quota){ cache.push(record.id, am_id.slice(0,am_id.length-5))} //I'm also assuming all of your unique-ids have exactly five digits appended to them from the right

Afterwards, you’d use that array to search through the other table for a partial match based on that am_id we’ve lifted.

let cache2 = [...cache] // always be making copies of your objects, it'll make debugging easier and JS garbage collection can take it
let q = await base.getTable('AM Quota').selectRecordsAsync()
for (let record of q.records){
//assuming those people's names are in the primary table field, otherwise just use the getCellValue method again

let check = cache.indexOf(record.name)
if(check!==-1){
cache2[check] = {id:record.id,name:record.name}
}

So, build an array of your records to update from here and you’re done, use the following syntax to handle 50 updates at a time instead of doing them one by one:

while(cache3.length) await base.getTable('YourFirstTableName').updateRecordsAsync(cache3.splice(0,50))

sidenote: while(x.length) is the same as writing while( x.length > 0 ){ … }, used to be a risky practice, nowadays even works in Safari for iOS

Cache3 being your final package in this example.

There’s probably like 10 easier ways to accomplish this but not enough info to speculate and tbh it sounds like you pretty much had things under control even before getting into the code itself.

But if you’ve had enough of it by now, then going the Automation route means getting the record.id way easier than this, just click your way through the “when record created/updated” condition and you’ll be golden in no time.