Spring Data Repositories

CrudRepository provides basic CRUD (save, find, delete, count); JpaRepository extends it with pagination, sorting, flush, batch delete, and lazy references – use JpaRepository for Spring Boot apps.

The Repository pattern abstracts data access behind an interface so business logic depends on the abstraction, not the persistence technology – enabling swappable stores, easy mocking, and clean separation.

CrudRepository is basic CRUD, PagingAndSortingRepository adds paging and sorting, and JpaRepository adds JPA batch and flush power.

DAO abstracts the data source table-by-table; Repository abstracts the domain as a collection of aggregates, and both hide persistence so the store is swappable and testable.