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Updating a Relation Property in a Notion Database using Custom Actions
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One of the limitations with the Update Database Item action in Notion’s standard Zapier integration is that it doesn’t allow you to update Relation properties. For example, you might have a Contacts database and a Companies database in a Notion CRM setup, and it saves a lot of time if you can automate linking records between the two based on a Contact’s email address and domain.
Fortunately, updating Relation properties is supported by Notion’s API, which means that you can pull this off by building a Zapier Custom Action:
What Are Zapier Custom Actions?
Zapier Custom Actions let you build your own action steps for existing apps when the default Zapier integration doesn’t offer exactly what you need. Here’s what makes them powerful:
- Go beyond built‑in options: Use an app’s public API to add missing functionality (e.g. updating relation properties in Notion)
- AI‑powered setup with Copilot: Describe what you want in plain English and Zapier’s AI builds the action for you
- Reusable and shareable: Once created, you can use your Custom Actions across multiple Zaps and with teammates
- Ideal for advanced workflows with no need to code: It offers more flexibility than webhooks or custom code steps, while still keeping things no‑code friendly and secure
Custom Actions are meant to be built with natural language prompts, so just create a new action, and tell the AI assistant something like:
Prompt for Building a Custom Action
Build an action to update a relation property in a Notion database. Allow the user to select the database from a drop-down menu. Then:
- Allow the user to provide the name of the relation property to update
- Allow the user to provide an array of Page IDs, which will be the values to update in the relation property.
While Notion’s native Zapier integration still has some limitations, Custom Actions unlock powerful capabilities, like dynamically updating relation properties across databases.
This can be a game-changer if you’re building automated CRMs or other linked systems in Notion. With just a few prompts and some testing, you’ll have a flexible, reusable action that saves time and reduces manual effort.
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