How I Solved a Knack Limitation While Building a Permit Milestone Tracker
I work at a construction company where we use Knack to digitize field operations and track key milestones across multiple projects.
Recently, I faced a tricky challenge while building a Permit Milestone Tracker.
The Problem:
Each permit has multiple milestones. When a new milestone (e.g., Line 2) is completed and we input the Actual Date, we want Line 1 (the previous milestone) to automatically update its End Date.
Seems simple, right?
Not in Knack.
Knack doesn’t allow record-to-record calculations in a child table. Meaning: you can’t reference one row to update another without extra logic. Pulling all the data into a parent table wasn’t feasible either — we needed the data to stay in a columnar format for the team to review at a glance.
Tools I Used:
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Knack Builder
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Knack Flow
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Grids with Inline Edit + Record Action
The Solution:
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User updates Line 2 with the “Actual Date.”
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A Knack Flow is triggered to find Line 1 and update its “End Date” with the new “Actual Date” from Line 2.
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Everything is now synced visually and functionally in the same child table grid.