From Multi-Select property to Relation of an other DB in Notion |

Hello everyone. I’m creating a scenario where I need to connect (relation property in Notion) starting from a multi-select. In practice I need it to automate the tagging that Readwise does for each content (with multi-select), connecting the content to my topic DB (via relation).

I’ll explain:

step 1: trigger when an item is added to the content DB. This page will have tags (multi-select properties) taken from Readwise.
step 2: I search in my “Topics” DB only for topics that have the same name (I made sure to use the same text in the Readwise tags)
step 3: I connect the topics found to the content of Step 1

How I set it up works only if I have 1 tag/topic connected. The problem arises when I put 2 or more tags. As step 2 only passes me only 1 tag (the first)(only 1 bundle). I assume it’s because it’s a multi-select, but I’m not sure

instead, I have to make sure that if I pass 2 or 3 tags to the content, step 2 finds them and then I can connect them with step 3.

I hope I was clear.

Thanks in advance,

Example with 2 tags

Step 1

Step 1 results (with the correct 2 Properties Value)

Step 2

Step 2 results (here I see only the first tag)

Step 3

Hi @Simone,
The mapping you have done in the search module will only look for the first item of the tags):

If you add an aggregator before the search module and add the Tags Array as source & adjust the mapping in the search module to the Array output, the search module will look for each tag and make the updates accordingly


hi, thanks for the reply. I tried but it didn’t work. I’ll send you a screenshot to explain:

array aggregator

result array aggregator

always 1 tag instead 2

and I think it’s because of the aggregator array, now in the last step I can’t recall the first ID

entire screen

Hi @Simone,
I’m so sorry I made a typo :face_with_peeking_eye: You have to use an iterator, which means you process bundles individually.


thank you!

now it works until the last step! but I have the last problem (I hope)…

in the end, I get 1 anyway… because by putting it as I did, in practice the first tag is placed first correctly, but then replaced by the second one.

how can I get both added?

step 2/3 correct

last step

thanks again you are very kind

I’m not sure if I understand the workflow correctly… My understanding was

  1. Content DB with multi select Tags property
  2. Topics DB where the names are aligned with the Tags property of the Content DB
  3. When you have a new item in Content DB, you want to relate this page to each relevant Topic. So if you have 2 tags you will update 2 pages in the Topics DB.
    → looking at your screenprint I assume you are updating the Content DB with the links to the related Topics pages.

Since you want to update the Content DB only 1 time, you will need an aggregator (so you will continue with 1 bundle only). In the mapping you have to merge the page IDs which you found in the search module. You can try the following function {{join( + “,”)}}


yes, thw worflow you described is corrects.

but I don’t understand your last part: where do I need to add the aggregator?

Between the search module and the Update the database item, so you can ‘merge’ the results of the search module into 1 value to update the Content DB

Edit: use the Iterator as Source module in the Aggregator and make sure to select at least the page ID as ‘aggregated field’


sadly, By setting it this way, the aggregator still makes 2 passes

also the last step doesn’t seem to do anything like that. in fact no topics are reported. I put “key” in topics field? otherwise I could choose my own values, but if I put the text (name) it gave me an error

You have to select the Iterator as the source, this way you will get 1 bundle out of the Aggregator.
You don’t have to fill the “Group by” in the aggregator
In the Update database item, you can use the formula to join the Page IDs


ok, I did as you described but nothing.

now aggregator pass 1 bundle

but nothing happens in the last step, no topics are added

output of last step

copy-pasting formulas here in the community and back to Make sometimes creates weird changes… The ‘+’ and the " should not be there…
Besides that, I think I was too fast with the formula (again :face_with_peeking_eye:) . Try this:
This actually outputs the array with the page ID that come from the aggregator. Maybe this is enough because I think the API for the topics expects an Array as well.
Hope this was the final step :crossed_fingers:


Since your trigger is grabbing all the tags at once, you’ll need to break them up into separate pieces. In, you can use a tool like a text parser to split up the tags. You just need to decide what you’re using to separate the tags, like a comma or a space, and the text parser will do the rest.


yes!!! works. thank you so much for your patience!


Which of the 2 methods would you recommend?