Event sourcing patterns

Event sourcing patterns bridge the gap between databases that need to be in sync. They help us track the changes across the system and act as a behind-the-scenes transport or lookup system to ensure that we always have the best data representation at any time.

First, an event represents a moment in time. The data contained in the event will indicate the type of action taken and the resulting data. This information can then be used for several reasons within the system:

• Complete tasks for third-party services that need the resulting data for their operations
• Update the database for query operations with the latest copy of the augmented record
• Add to an event store as a versioning mechanism

Event sourcing can play several roles in a system and can aid us in completing several routines and unique tasks. Routine tasks within the context could include updating our read-only query database and acting as a source of truth for services that...