> ## Documentation Index
> Fetch the complete documentation index at: https://docs.dqlabs.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Use Cases

> Real-world Lookup metric examples in Prizm — product catalog integrity, ISO country code validation, and cross-source customer ID checks.

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## Example use cases

**Product catalog integrity:** The `orders.product_id` column should reference only valid products in the `products` table. A Lookup metric with 100% pass criteria alerts the moment any order references a non-existent product — catching orphaned records from a failed product sync before they break pricing and fulfillment.

**ISO country code validation:** A CRM stores `country_code` for every customer. A Lookup metric validates each value against a static Reference File of valid ISO 3166-1 alpha-2 codes. When a data entry team begins entering full country names instead of codes (`"United States"` instead of `"US"`), the match rate drops and Prizm alerts — surfacing a process breakdown before it corrupts segmentation reports.

**Cross-source customer ID validation:** A fact table's `customer_id` column is validated against a CRM API. New IDs appearing in the fact table that don't exist in the CRM surface orphaned records from a failed sync or a test data leak into production.

<Tip>
  Use Lookup metrics for any column that represents a foreign key relationship not enforced at the database level — product codes, account IDs, country codes, status values drawn from a master data table. These violations are common in warehouses and lakehouses where FK constraints are disabled for performance.
</Tip>