Multi-tier XML record retrieval and editor architecture with presentation, application, and data layers handling HTTP requests through WAF and load balancing. The application tier parses XML via PHP, builds DOM objects, applies XSD schema validation and XSLT transformations to generate HTML forms for client editing. Data tier integrates local and external SRU protocol databases, XML record stores, and schema/stylesheet repositories to support federated XML document management. This architecture demonstrates enterprise patterns for secure, scalable XML processing with schema-driven validation and presentation layer abstraction. Fork this diagram on Diagrams.so to customize database endpoints, add caching layers, or extend the SRU protocol handlers for your metadata systems. The separation of XSD schema loading, XSLT transformation, and form generation enables reusable component design across multiple XML document types.