Repositories

Advanced repository patterns and best practices.

Basic Repository Interface

@Repository
public interface UserRepository extends JpaRepository<User, Long> {
    // Built-in methods: save, findById, findAll, delete, count, etc.
}

Method Name Query Generation

Sproogy generates queries from method names:

@Repository
public interface UserRepository extends JpaRepository<User, Long> {

    // SELECT * FROM users WHERE username = ?
    Optional<User> findByUsername(String username);

    // SELECT * FROM users WHERE age > ?
    List<User> findByAgeGreaterThan(int age);

    // SELECT * FROM users WHERE username = ? AND active = ?
    Optional<User> findByUsernameAndActive(String username, boolean active);

    // SELECT * FROM users WHERE email LIKE %?%
    List<User> findByEmailContaining(String emailPart);

    // SELECT * FROM users ORDER BY created_at DESC
    List<User> findAllByOrderByCreatedAtDesc();

    // DELETE FROM users WHERE status = ?
    @Transactional
    void deleteByStatus(String status);

    // SELECT COUNT(*) FROM users WHERE active = ?
    long countByActive(boolean active);
}

Supported Keywords

Keyword	Example	Generated SQL
And	findByNameAndEmail	WHERE name = ? AND email = ?
Or	findByNameOrEmail	WHERE name = ? OR email = ?
GreaterThan	findByAgeGreaterThan	WHERE age > ?
LessThan	findByAgeLessThan	WHERE age < ?
Between	findByAgeBetween	WHERE age BETWEEN ? AND ?
Like	findByNameLike	WHERE name LIKE ?
Containing	findByNameContaining	WHERE name LIKE %?%
StartingWith	findByNameStartingWith	WHERE name LIKE ?%
EndingWith	findByNameEndingWith	WHERE name LIKE %?
OrderBy...Asc	findAllByOrderByNameAsc	ORDER BY name ASC
OrderBy...Desc	findAllByOrderByNameDesc	ORDER BY name DESC

Custom Queries

For complex queries, use @Query:

@Query("SELECT u FROM User u WHERE u.createdAt > :date ORDER BY u.createdAt DESC")
List<User> findRecentUsers(@Param("date") Date date);

See Queries for more examples.

Best Practices

✅ Use method names for simple queries ✅ Use @Query for complex queries ✅ Return Optional<T> for single results that might not exist ✅ Use @Transactional for delete/update methods

Next Steps

👉 Custom Queries - Write JPQL and native SQL 👉 Transactions - Manage transactions properly