How to Build Notion Relation Hierarchy for Parent-Child Page Tree

When you manage projects, departments, or nested tasks in Notion, a flat list of pages quickly becomes unmanageable. You need a structured parent-child page tree that shows how items relate to each other at a glance. Notion provides two database property types—Relation and Rollup—that let you create this hierarchy without manually linking pages. This article … Read more

Fix Notion Rollup Cannot Aggregate Multi-Select: Workaround Pattern

You have a Notion database with a multi-select property and want to use a rollup property to count or sum values from that field. Notion rollup properties cannot directly aggregate multi-select fields — the rollup will show “Cannot aggregate multi-select” as an error or return blank. This limitation exists because multi-select properties hold multiple values … Read more

Why Notion Relation Drag-and-Drop Reordering Causes Schema Lock

Notion users often find that after dragging and dropping a relation property to reorder it in the database schema, the entire database becomes uneditable for several minutes. The property menu stops responding, new rows cannot be added, and existing data appears frozen. This behavior is not a random bug but a deliberate schema lock triggered … Read more

Fix Notion Rollup Showing Wrong Sum: Type Coercion Diagnosis

When a Notion rollup property displays an incorrect sum, the most common cause is type coercion. Notion automatically converts data types when rolling up values from related database properties, and this conversion can turn numbers into text or text into numbers. This article explains how type coercion works in Notion rollups, how to diagnose it, … Read more

How to Use Notion Relation in Formula 2.0 With Lambda Expression

Notion Formula 2.0 introduced the ability to work with relation properties directly inside formulas using lambda expressions. Before this update, you could only reference a relation property to count or check existence, but you could not filter, map, or reduce the linked items. This article explains how to write lambda expressions that operate on relation … Read more