A three-tier data warehouse architecture provides a structured framework for collecting, integrating, storing, and analyzing healthcare data. It enables hospitals and healthcare organizations to transform large volumes of operational data into meaningful information for clinical, administrative, and strategic decision-making. The architecture consists of the bottom tier, middle tier, and top tier, each performing specific functions. The bottom tier includes data sources, the staging area, ETL processes, metadata repository, and the data warehouse. Data sources are the origin of information collected from various healthcare systems. These sources include Electronic Health Records (EHRs), Hospital Information Systems (HIS), Laboratory Information Systems (LIS), Pharmacy Management Systems, Radiology Information Systems, billing systems, insurance databases, patient registration systems, wearable devices, and external public health databases. Since these sources use different formats and technologies, direct analysis is difficult. The staging area acts as a temporary storage location where data from multiple sources is collected before being loaded into the warehouse. It isolates operational systems from warehouse processing and allows data cleaning, validation, integration, and transformation without affecting daily hospital operations. The staging area also removes duplicate records, resolves inconsistencies, and prepares data for further processing. The ETL (Extract, Transform, Load) process is the core mechanism of