It gives me great pleasure to present this volume as Module 6 of the Modular Geospatial Series, a structured ten-module programme designed to guide readers from the foundations of Geographic Information Systems to the advanced architectures that power modern geospatial infrastructures. Each module addresses a distinct domain of spatial technology, while together they form a comprehensive pathway through contemporary geospatial engineering. This volume occupies a particularly important position within that journey because spatial databases represent the point where geographic information transitions from static data into scalable, operational systems.