Design pattern for mapping database in Data Access Layer [C#]

Question

I work on my Data Access Layer where I use data mapper pattern. My actual structure of code is for example:

public class Person {
    public int Age
    public string FirstName
    public string LastName
    public List<Address> Addresses
    ...
}

public class PersonMapper {
    public Person GetPersonById(int id)
    public List<Person> GetAll()
    public bool UpdatePerson(Person person)
    ...
}

I have so many classes which are corresponding for database table with same name.

My questions are:

Is my approach right? When I mapped all tables, I will use it in the domain layer.
In Mapper classes I use methods which are working only with tables which are same name as these classes. (Person class -> Persons db table, Order class -> Orders db table, etc.) But what is the best way to map advanced selects from database, which will be contains joins to more tables. For example I want select Person with all his Orders. Should I create domain model for Person which will be contains property List<Orders>and use PersonMapper and next OrderMapper?

I'm not sure why it's called a mapper. To me personally it's a repository. And if I could, I'd use entity framework which does all that for me. — Alex G., Dec 07 '16 at 11:40
@DenisStephanov: In `DataAccessLayer` world, your `PersonMapper` class is generally called `PersonRepository`. The word `Mapper` have different meaning in `DAL`. — Amit Joshi, Dec 08 '16 at 05:16
So should I rename it? How is different between repository and mapper ? :/ I am lost in it — Denis Stephanov, Dec 09 '16 at 11:37

score 3 · Accepted Answer · answered Dec 16 '16 at 13:15

See the DAO Pattern.

In general: For every table in your db you have an entity and a Dao class for the entity also a database class which communicates with the database.

For example Person, PersonDao, Database.

The person is the entity. PersonDao uses Database class to query database only for person table. Database is a CRUD class for the database.

Design pattern for mapping database in Data Access Layer [C#]

1 Answers1