Code First Default Values

Question

How do I set a default value in code first?

[Required]
[DefaultValue(-1)]
public int PostStatusID { get; set; }

How do I set the default value on deletion?

    builder
        .Entity<Post>()
        .HasOne(e => e.Status)
        .WithOne(e => e.AssignedPost)
        .OnDelete(DeleteBehavior.SetDefault);

This code doesn't work.

Cascade is not going to work because I do not want a post deleted just because a status was deleted. So I need another option. I can't set the value to null, so I need to set it to a default value, or I need to prevent a status from being deleted while a post is referencing it as a foreign key.

OnDelete(DeleteBehavior.Restrict)

Is restrict going to prevent a status from being deleted while a post is referencing it? The description of this value isn't clear to me.

Answer 1

@CodeXennial , you could try the following code to set the default value in code first.

public class Student  
    {  
  
        [Key]  
        public int Id { get; set; }  
        public int PostStatusID { get; set; }  
  
          
        public string Name { get; set; }  
  
    }  
  
    public class StudentContext:DbContext  
    {  
        public DbSet<Student> students { get; set; }  
  
        protected override void OnModelCreating(ModelBuilder modelBuilder)  
        {  
            modelBuilder.Entity<Student>()  
                .Property(b => b.PostStatusID)  
                .HasDefaultValue(-1);  
        }  
        protected override void OnConfiguring(DbContextOptionsBuilder builder)  
        {  
            builder.UseSqlServer("connstr");  
        }  
    }  

Result in database design:

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