Module 4 of 6 · 10 min

# Lineage Basics

How to trace a number back to where it came from, at both table and column level.

## Why this matters

Lineage answers two questions: where did this figure come from, and what breaks if this table changes. Without it, you ask whoever has been at the company longest.

## Before you start

### Lineage is a graph, and direction matters

Upstream is where data comes from, downstream is what depends on it. Both directions answer different questions. Upstream answers "can I trust this", because it shows you the sources and transformations behind a figure. Downstream answers "what will I break", which is the question to ask before changing or deprecating anything.

### Column level lineage is where the real answers are

Table level lineage tells you that a report depends on an orders table. Column level lineage tells you that the revenue figure on that report is derived from a specific column, through a specific transformation. When two dashboards disagree about revenue, table lineage will not resolve it and column lineage usually will.

### Lineage is collected, so it can have gaps

Lineage is built by an agent parsing queries, pipeline definitions and transformation code. Where that parsing succeeds the graph is reliable. Where a transformation happens somewhere the agent cannot see, in a spreadsheet or an undocumented script, the graph will show a break. A gap in the graph marks an unmanaged step in the path.

## The interactive demo

Work through the demo below. It runs in your browser with nothing to install. Watch for:

*   •The basics of how data lineage is represented
*   •Configuring the Lineage Agent
*   •Navigating table level and column level lineage

This demo is also available on its own at [the Learning Center](/learning-center/product-demo-lineage).

## After this module you should be able to

*   ✓Trace an asset upstream to its sources and downstream to its consumers
*   ✓Use column level lineage to explain how a specific figure is derived
*   ✓Recognize a gap in a lineage graph and understand what it implies