CODEWITHSUNDEEP
c#entity-frameworkef-code-first
John Freebs
John Freebs

Reputation: 447

Entity Framework (Code First) recursive parent

I am trying to describe a tree like structure where each item is a node in the tree and can (or not) have a parent.

When describing the Node entity, this works:

public class Node
{
    public int Id {get;set;}
    public string Description {get;set;}
    public int ParentId {get;set;}
}

I get a table called Nodes with the above columns and a PK on Id. If I then add a new parameter:

public virtual Node Parent {get;set;}

for quick/easy access to the parent node, the creation code adds a foreign key constraint requiring ParentId to point to a Node Id.

Since some nodes will not have a parent, attempting to add a Node with a ParentId of 0 fails.

Is there a way to do this?

Upvotes: 0

Views: 352

Answers (1)

Technovation
Technovation

Reputation: 397

do you have any restriction in your data model? if not just try to make parentId nullable as this:

   public int? ParentId {get;set;}

Upvotes: 2

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