Description

The Identity Field design pattern ensures that each object in a system has a unique identifier, which can be used to track the object independently of its database representation. This pattern is particularly useful in systems where objects need to be reconstituted from a persistent storage medium, ensuring that each object retains its unique identity across different sessions and operations.

Main Elements of the Pattern:

1. Unique Identifier: Each object is assigned a unique identifier, typically a primary key in the database.
2. Field Mapping: The identifier field in the object corresponds to a unique column in the database table.
3. Object Persistence: Ensures that the unique identifier is consistently used when saving and retrieving objects from the database.

References

• Martin Fowler's Identity Field
• Source Code Examples - Identity Field Pattern
• Project Contribution Guidelines

Acceptance Criteria

1. Unique Identifier Implementation: Each domain object must have a unique identifier field that maps to the primary key in the database.
2. Persistence Mechanism: Implement a mechanism to ensure that objects are saved and retrieved using their unique identifiers, maintaining consistent identity across sessions.
3. Unit Tests: Provide comprehensive unit tests to validate the correct assignment, persistence, and retrieval of the unique identifiers for domain objects.