---
title: "What is a dependency graph?"
description: "A dependency graph records which columns depend on which, so an edit invalidates only descendants."
url: "https://pixeltable.com/learn/what-is-a-dependency-graph"
updated: "2026-09-29"
vertical: "Orchestration"
doc: "https://docs.pixeltable.com/datastore/computed-columns"
---

# What is a dependency graph?

A dependency graph records which columns depend on which, so an edit invalidates only descendants.

Updated: 2026-09-29
Part of [What is a computed column?](https://pixeltable.com/learn/what-is-a-computed-column).

## On this page

- [How it works](https://pixeltable.com/learn/what-is-a-dependency-graph#how-it-works)
- [What it is not](https://pixeltable.com/learn/what-is-a-dependency-graph#what-it-is-not)
- [Comparison](https://pixeltable.com/learn/what-is-a-dependency-graph#comparison)
- [Where Pixeltable fits](https://pixeltable.com/learn/what-is-a-dependency-graph#where-pixeltable-fits)
- [Questions](https://pixeltable.com/learn/what-is-a-dependency-graph#questions)

## How it works {#how-it-works}


- Each computed column names its inputs.
- The graph is the set of those edges.
- Invalidation follows the edges from the edited value.

## What it is not {#what-it-is-not}

It is not a task DAG you schedule, and it is not a README that describes the pipeline.

## dependency graph: this, and the thing it is confused with {#comparison}

|  | This | Not this |
| --- | --- | --- |
| Nodes | Columns and rows | Jobs |
| You edit | A value or an expression | A schedule |
| Effect | Descendant rows | Every downstream job |

## Where Pixeltable fits {#where-pixeltable-fits}

Pixeltable builds that graph from the expressions on the classes. The local dashboard can show it.

## Questions {#questions}

### How does dependency graph work? {#faq-1}

Each computed column names its inputs. The graph is the set of those edges. Invalidation follows the edges from the edited value.

### What is dependency graph often confused with? {#faq-2}

It is not a task DAG you schedule, and it is not a README that describes the pipeline.

## In the blog

- [Browse and Debug Multimodal Pipelines with the Pixeltable Local Dashboard](https://pixeltable.com/blog/pixeltable-local-dashboard-browse-debug-pipelines)
- [Your Agent Needs a Data Plane, Not a Dashboard](https://pixeltable.com/blog/agent-data-plane-not-dashboard)
- [The Invisible 80%: Why Your AI Agent Demo Won't Survive Production](https://pixeltable.com/blog/invisible-infrastructure-production-ai-agents)

## Related

- [Documentation](https://docs.pixeltable.com/datastore/computed-columns)
- [Dependency Graph Magic: How Pixeltable Keeps Your AI Pipeline Data Consistent](https://pixeltable.com/blog/dependency-graph-magic-computed-columns)
- [Browse and Debug Multimodal Pipelines with the Pixeltable Local Dashboard](https://pixeltable.com/blog/pixeltable-local-dashboard-browse-debug-pipelines)
- [Declarative data infrastructure](https://pixeltable.com/use-cases/declarative-ai-data-infrastructure)