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Workday architecture

The Workday Architecture: A Metadata-Driven Object Model

These articles describe a very specific and revolutionary (at the time) architecture that differs fundamentally from the relational database-centric world of SAP and Oracle. The key pillars of Workday’s architecture are:

  1. In-Memory Object Model: Workday does not use a traditional relational database (like Oracle, SQL Server) for its primary operations. Instead, its core is an application server, the Object Management Services (OMS), that runs a live, in-memory graph of interconnected “business objects.”
  2. Business Objects: The system is not built on tables and joins, but on high-level business concepts like Employee, Organization, Position, Invoice, Benefit Plan, etc. These are the “nouns” of the business. They have data fields (attributes) and, crucially, persistent relationships to other objects.
  3. Metadata-Driven Engine: This is the core of their solution. The definitions of all business objects, their relationships, business rules, validation logic, and even the user interface are not hard-coded. They are stored as metadata. The OMS reads this metadata at runtime to construct the application. When Workday wants to add a new feature (e.g., a new type of leave for a specific country), they primarily update the metadata, not the core application code.
  4. The “Power of One”: Because all customers run on the same single codebase and a unified (though configurable) data model, there are no versions and no painful integrations between separate HR and Finance modules. All data is in one place, accessible in real-time.
  5. Effective Dating: Time is a native concept. Every change to an object is timestamped, allowing the system to view the state of the business at any point in time—past, present, or future—without complex queries.

Page last modified: 2025-10-04 11:51:12