Table of Contents

Data Column Must Have Source

  • 2026-01-09
  • Morten Lønskov

Overview

This best practice rule identifies data columns that lack a valid SourceColumn property. Every data column must reference a source column from the underlying data source to function correctly during refresh.

  • Category: Error Prevention
  • Severity: High (3)

Applies To

  • Data Columns

Why This Matters

  • Refresh failures: Data refresh operations fail with column not found errors
  • Deployment issues: Model validation fails in Power BI Service or Analysis Services
  • Data integrity: Column remains empty or contains stale data
  • Broken dependencies: Measures and relationships produce incorrect results

When This Rule Triggers

The rule triggers when a data column has:

string.IsNullOrWhitespace(SourceColumn)

How to Fix

Manual Fix

  1. In TOM Explorer, locate the flagged data column
  2. In Properties pane, find the Source Column property
  3. Enter the correct source column name from your data source query
  4. Verify the mapping matches the partition query

The source column name must exactly match:

  • For Power Query: Column name in M expression output
  • For SQL: Column name or alias in SELECT statement
  • For Direct Lake: Column name in Delta Lake table

Common Causes

Cause 1: Renamed Source Column

Source query was modified and column renamed.

Cause 2: Manual Column Creation

Column created manually without specifying source.

Cause 3: Copy/Paste Corruption

Columns copied from another table without preserving metadata.

Example

Before Fix

Table: Sales
Column: ProductName (DataColumn)
  SourceColumn: [empty]

Result: Refresh fails with "Column 'ProductName' not found in source query"

After Fix

Table: Sales
Column: ProductName (DataColumn)
  SourceColumn: ProductName

Result: Column populates correctly during refresh

Compatibility Level

This rule applies to models with compatibility level 1200 and higher.