repositorymallit

Repositorymallit, or repository patterns, are a family of software design patterns used to abstract data access within an application. They provide a collection-like interface for retrieving and persisting domain objects, decoupling business logic from the details of storage and data mapping. A repository acts as a gateway between the domain model and the data source, hiding whether data comes from a relational database, a NoSQL store, or an external service.

Typically, a repository exposes operations such as add, update, remove, getById, getAll, and query methods. More advanced variants support specification-based queries or expression-based filtering. In domain-driven design, repositories are often used to manage aggregate roots and to preserve a clean separation between the domain layer and the persistence layer. They are frequently used together with a unit of work to coordinate transactions.

Variants include a generic repository that handles multiple entity types and specific repositories for particular aggregates. The decision to use repositorymallit involves weighing the benefits of decoupling and testability against the risk of over-abstraction, leakage of persistence concerns, and potential performance pitfalls. Critics warn that repositories can become an anemic abstraction if they simply mirror ORM capabilities instead of modeling domain queries.

Examples: an interface Repository<T> with methods GetById, GetAll, Add, Remove, and Find; concrete implementations map to ORMs such as Entity Framework, Hibernate, or direct SQL. In modern architectures, some teams favor domain services, CQRS, or query builders over generic repositories for complex data access.