public interface ICarDal { int CreateCar(Car car); Car GetCarById(int id); IEnumerableThe above code defines the ICarDal interface with five methods: - `CreateCar`: Inserts a new car entity into the database and returns the ID of the newly inserted record. - `GetCarById`: Retrieves a car entity from the database based on its ID. - `GetAllCars`: Retrieves all car entities from the database. - `UpdateCar`: Updates an existing car entity in the database. - `DeleteCar`: Deletes a car entity from the database based on its ID. The package library for ICarDal would depend on the specific database that is being used to store the car entities. For example, if the application is using Microsoft SQL Server, the package library might be Microsoft.Data.SqlClient or System.Data.SqlClient. If the application is using PostgreSQL, the package library might be Npgsql.GetAllCars(); void UpdateCar(Car car); void DeleteCar(int id); }