A central repository that consolidates data from multiple sources, optimized for reporting and analysis.
Unlike an operational database designed for day-to-day transactions, a data warehouse is built for querying large volumes of historical data quickly. Data is loaded from source systems through ETL processes, cleaned, and organized into a structure that supports business intelligence and analytics.
Data warehouses typically store months or years of data and are designed so that analysts can run complex queries without slowing down production systems.
Example: A provincial health authority consolidates patient visit records from dozens of hospitals into a data warehouse. Analysts query it to identify trends in emergency room wait times across regions — something impossible to do efficiently from individual hospital databases.
Data warehouses are a key reason why large organizations can produce consistent, reliable reports across departments and time periods.