How do I create a relation between databases in Notion?

Creating relations between databases in Notion transforms isolated information into a connected workspace that works smarter, not harder. This powerful feature lets you link related data across different databases—connecting projects to tasks, clients to campaigns, or any combination that matches your workflow. While the process might seem complex initially, understanding how to build these connections opens up possibilities for automated data aggregation and streamlined organization. We'll walk through the essential steps and considerations to help you create meaningful database relationships that enhance your productivity.

To create a relation between two databases, start by adding a new property to your source database. Click the "+ Add a property" button, give it a descriptive name like "Related Project" rather than generic terms, and set the property type to "Relation." Notion will prompt you to select which database you want to connect to—choose carefully, as selecting the wrong target database is a common mistake that can create confusion later. Once you've selected your target database, you'll need to decide whether to create a one-way or two-way relation by toggling the "Show on [other database]" option.

The choice between one-way and two-way relations significantly impacts how your data behaves. Two-way relations create mirrored connections, meaning changes appear in both databases and enable seamless collaboration across different views. This works particularly well for project management scenarios where team members need to access related information from either direction. However, one-way relations keep things simpler when you only need information to flow in a single direction, such as linking tasks to their parent projects without cluttering the projects database with individual task references.

Once your relation property is configured, populate it by clicking in the relation column for each row and selecting the appropriate entries from your connected database. You can enhance these connections further by adding rollup properties, which automatically aggregate data from related records—perfect for calculating project completion percentages or summing budgets across linked items. Consider setting limits on your relation properties when only one connection makes sense, such as assigning a single owner to each task.

While database relations unlock powerful organizational capabilities, they come with important considerations. Large numbers of interconnected relations can slow down your workspace performance, especially across hundreds of records with complex cross-linking. Start simple and build complexity gradually, regularly auditing your database structure to remove unused relations. When implemented thoughtfully, database relations transform Notion from a collection of separate tables into an integrated system where your information works together seamlessly, supporting more sophisticated workflows and better insights across your projects.