Sekiban DCB Tutorial: Building Materialized Views for Event-Sourced Systems

A developer tutorial published on DEV Community demonstrates how to implement Materialized Views (MVs) using the Sekiban DCB framework on a student enrollment management system. The system stores actions such as student creation, profile updates, and class enrollments as events, which are then projected into read-side SQL tables for efficient querying. Built on a stack of .NET 10, Sekiban DCB 10.19.0, Orleans, and PostgreSQL, the implementation uses separate databases for the event store and the MV, allowing enrollment data to be retrieved via SQL JOINs across student, class, and enrollment tables. Because event persistence and MV updates run as separate processes, a delay exists between a successful write command and the updated data becoming visible on the read side. The tutorial emphasizes that MVs are intended solely for reading and should never be used to enforce business rules or validate consistency, as the event store remains the single source of truth.