[ASP.Net Core] Entity Framework Core 2 - LINQ ( Include , ThenInclude )

SQL 쿼리문에서 Join 문과 같이 관계가 연결되있는 부분을 LINQ 의 Include 와 ThenInclude 를 통하여 불러올수 있는데, 이에  좋은 포스팅 글이 있어서 소개한다.

 

https://entityframeworkcore.com/querying-data-include-theninclude

EF Core Include - Learn How to Retrieve Related Objects in LINQ

 

public class Customer
{
    public int CustomerId { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Address { get; set; }
    public virtual List<Invoice> Invoices { get; set; }
}
 
public class Invoice
{
    public int InvoiceId { get; set; }
    public DateTime Date { get; set; }
    public int CustomerId { get; set; }
    [ForeignKey("CustomerId")]
    public Customer Customer { get; set; }
    public List<InvoiceItem> Items { get; set; }
}
 
public class InvoiceItem
{
    public int InvoiceItemId { get; set; }
    public int InvoiceId { get; set; }
    public string Code { get; set; }
    [ForeignKey("InvoiceId")]
    public virtual Invoice Invoice { get; set; }
}
 
Controller 에서
 
var customer = db.Customers.Single(c => c.CustomerId == cid);
 
var invoices = db.Customers.Include(c => c.Invoices).ThenInclude(c2 => c2.InvoiceItems)
                .Where(c3 => c3.CustomerId == cid).ToList();
 

 

 

https://learn.microsoft.com/ko-kr/ef/core/querying/related-data/eager

관련 데이터의 즉시 로드 - EF Core

https://learn.microsoft.com/ko-kr/ef/core/modeling/entity-types?tabs=data-annotations 

엔터티 형식 - EF Core

 

[ MS 의 아주 좋은 EF 예제 ] - 다대다 관계 등 다양한 내용 수록

 

https://learn.microsoft.com/ko-kr/aspnet/core/data/ef-mvc/complex-data-model?view=aspnetcore-6.0 

자습서: 복잡한 데이터 모델 만들기 - ASP.NET MVC 및 EF Core 사용

 

 

using (var context = new BloggingContext())
{
    var blogs = context.Blogs
        .Include(blog => blog.Posts)
        .Include(blog => blog.Owner)
        .ToList();
}
 
 
using (var context = new BloggingContext())
{
    var blogs = context.Blogs
        .Include(blog => blog.Posts)
        .ThenInclude(post => post.Author)
        .ThenInclude(author => author.Photo)
        .Include(blog => blog.Owner)
        .ThenInclude(owner => owner.Photo)
        .ToList();
}

 

https://www.tutorialsteacher.com/linq/what-is-linq

What is LINQ

 

https://www.tutorialsteacher.com/linq/linq-method-syntax

LINQ Method Syntax

 

https://www.tutorialsteacher.com/linq/linq-lambda-expression

Anatomy of the Lambda Expression

 

 

 

[ DTO 관련 내용 설명 ]  

https://www.telerik.com/blogs/dotnet-basics-dto-data-transfer-object

.NET Basics: DTO (Data Transfer Object)

 

 

[ EF Core Performance Optimization Challenge ]

https://www.youtube.com/watch?v=jSiGyPHqnpY 

https://github.com/StefanTheCode/OptimizeMePlease

GitHub - StefanTheCode/OptimizeMePlease

 

 

 

 

 

참고 : https://dleunji.tistory.com/45?category=999005

참고 : https://learn.microsoft.com/ko-kr/aspnet/core/data/ef-mvc/read-related-data?view=aspnetcore-6.0

참고 : https://github.com/dotnet/AspNetCore.Docs/tree/main/aspnetcore/data/ef-mvc/intro/samples/cu-final

 

ASP.NetCore 깃허브 자료실

https://github.com/dotnet/AspNetCore.Docs

GitHub - dotnet/AspNetCore.Docs: Documentation for ASP.NET Core