Data Quality Checks (DQCs): A Guide for Data Engineers Part 2 — Type 2 Tables

In Part 1 of this series, we explored the fundamentals of Data Quality Checks (DQCs) and covered essential checks like duplicates, counts, and sums for standard tables. Today, we’re diving deeper into a more complex but crucial topic: Data Quality Checks for Type 2 Slowly Changing Dimensions (SCD Type 2) tables.

Data Quality Checks (DQCs): A Guide for Data Engineers

If you work with financial data, customer information, or any scenario where you need to track how data changes over time, Type 2 tables are probably part of your daily life. But with great power comes great responsibility — and the need for specialized quality checks.

What Are Type 2 Tables?

Imagine you’re keeping a diary about your best friend. Instead of erasing and rewriting entries when something changes about them (like their address or phone number), you write a new entry while keeping the old ones. This way, you have a complete history of how things have changed over time.