Table of Contents

Remove Auto Date Tables

  • 2026-01-09
  • Morten Lønskov

Overview

This best practice rule identifies automatically generated date tables created by Power BI Desktop. These auto-generated tables (DateTableTemplate_ and LocalDateTable_) should be removed in favor of a single, explicit date table to optimize model size and performance.

  • Category: Performance

  • Severity: Medium (2)

Applies To

  • Tables
  • Calculated Tables

Why This Matters

Power BI automatically creates hidden date tables for every date/datetime column when "Auto Date/Time" is enabled. This causes issues:

  • Increased model size: Each auto-generated table adds unnecessary data
  • Memory overhead: Multiple date tables consume more memory than one shared table
  • Slower refresh: Additional tables increase refresh duration

A single, well-designed date table is far more efficient and maintainable.

When This Rule Triggers

The rule triggers when it finds calculated tables with names that:

  • Start with "DateTableTemplate_", or
  • Start with "LocalDateTable_"

These prefixes indicate Power BI's automatically generated date tables.

How to Fix

Manual Fix

  1. Disable Auto Date/Time in Power BI Desktop (File > Options > Data Load)
  2. Create a dedicated date table.
  3. Mark it as a date table and create relationships to fact tables
  4. In TOM Explorer, delete tables starting with DateTableTemplate_ or LocalDateTable_
  5. Verify custom date table relationships work correctly

Common Causes

Cause 1: Auto Date/Time Feature Enabled

Power BI Desktop's "Auto Date/Time" feature automatically creates these tables.

Cause 2: Migrated Models

Models created with auto tables enabled and never cleaned up.

Cause 3: Default Settings

New models use default settings which enable auto date tables.

Example

Before Fix

Tables:
  - Sales
  - LocalDateTable_OrderDate (hidden, auto-generated)
  - LocalDateTable_ShipDate (hidden, auto-generated)
  - Products
  - LocalDateTable_ReleaseDate (hidden, auto-generated)

Result: Multiple hidden tables inflate model size

After Fix

Tables:
  - Sales
  - Products
  - DateTable (explicit, marked as date table)
    -> Relationships to Sales[OrderDate], Sales[ShipDate], Products[ReleaseDate]

Result: Single efficient date table serves all date relationships

Compatibility Level

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

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