To Initialize or Not to Initialize Navigation Properties in EF Core: Which Approach is Best?

EF Core navigation attribute initialization: the best practice

In EF Core, there are two ways to initialize navigation attributes:

Method 1: Do not initialize

This method does not initialize navigation attributes in POCO (ordinary old CLR object):

Method 2: Initialize in the constructor

<code class="language-csharp">public class User
{
    public int Id { get; set; }
    public string UserName { get; set; }
    public virtual ICollection<Address> Addresses { get; set; }
    public virtual License License { get; set; }
}</code>

This method initializes navigation attributes in POCO's constructor:

Question 1: Which method is better?

For the collection attribute (such as addresses), there is no difference in functionality one and method two in method one and method two. Initialization does not affect business logic.

<code class="language-csharp">public class User
{
    public User()
    {
        this.Addresses = new List<Address>();
        //this.License = new License();  //对于引用属性，不建议初始化
    }
    public int Id { get; set; }
    public string UserName { get; set; }
    public virtual ICollection<Address> Addresses { get; set; }
    public virtual License License { get; set; }
}</code>

For reference attributes (such as License), it is not recommended to use it. It may cause unexpected behaviors, such as empty entities or partial loaded entities to be saved into the database. Question 2: How to determine the direction of navigation attributes?

In such a two -way relationship between User and License, if both classes initialize each other's navigation attributes, stack overflow may occur. To avoid this, one of the navigation attributes should be removed (in this example, the attributes in sub -entities) should be removed. This decision should be based on business rules and related directions.

The advantages and disadvantages are compared with

Method 1 (not initialization):

Advantages:

The entity that prevent the preservation of the empty entity or partial loaded

Avoid empty reference abnormalities Easy to delay loading

Disadvantages:

• For a short value check when it needs to be explicitly loaded
• Can't prevent relationship repair
Method II (initialization in the constructive function, but only the collection attribute):

Advantages:

• Simplified collection management
• No short reference abnormality

Disadvantages:

It may cover the loaded value Can't prevent relationship repair

It may lead to the problem of include and seed data in EF Core
• In short, there is no significant difference between the setting navigation attributes or not; for reference navigation attributes, it is recommended not to initialize in the constructor to avoid potential problems. The method to choose depends on the specific business needs and project structure.

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