Question

This Content is from Stack Overflow. Question asked by Osama Ahmed

I have entity called activity contains 2 list of models will be saved as json on db
i faced exception when i get entity say that :

 [ERR] The entity type 'LicenseModel' requires a primary key to be defined. If you intended to use a keyless entity type, call 'HasNoKey' in 'OnModelCreating'. For more information on keyless entity types, see https://go.microsoft.com/fwlink/?linkid=2141943.
   System.InvalidOperationException: The entity type 'LicenseModel' requires a primary key to be defined. If you intended to use a keyless entity type, call 'HasNoKey' in 'OnModelCreating'. For more information on keyless entity types, see https://go.microsoft.com/fwlink/?linkid=2141943.

so licenseModel is not configured as entity it’s column why he see as entity.
i figure that DateTime Properties in LicenseModel make this issue happend, when i change type to DateOnly or DateTimeOffset the issue not happend.

i used entity framework core version 6.0.7

i can use [Keyless] attibute on model or configure model in dbcontext
like this builder.Entity().HasNoKey(); but i need to
know why he see model as entity.

Entity Configuration

public class ActivitiesConfiguration : IEntityTypeConfiguration<Activities>
    {
        public void Configure(EntityTypeBuilder<Activities> builder)
        {
            builder.ToTable(nameof(Activities), DbSchema).HasKey(b => b.RequestId);
            builder.ConfigureByConvention();
            builder.Property(x => x.RequestId).IsRequired();
            builder.Property(x => x.Licenses).HasConversion(x => x.ToJSON(), x => x.ToModel<List<LicenseModel>>());
            
        }
    }

Entity

public class Activities : AuditedEntityTimeWithoutId
    {
        public Guid RequestId { get; private set; }
        public List<LicenseModel> Licenses { get; private set; }
        
    }

Model

public class LicenseModel
    {
        public string LicenseNumber { get; private set; } 
        public DateTime IssueDate { get; private set; } 
        public DateTime ExpireDate { get; private set; }
    }

Thanks For Support.

Solution

This exception message doesn’t mean it requires a primary key to be defined in your database, it means it requires a primary key to be defined in your class.

Although you’ve attempted to do so:

private Guid _id;
[Key]
public Guid ID
{
    get { return _id; }
}

This has no effect, as Entity Framework ignores read-only properties. It has to: when it retrieves a Fruits record from the database, it constructs a Fruit object, and then calls the property setters for each mapped property. That’s never going to work for read-only properties.

You need Entity Framework to be able to set the value of ID. This means the property needs to have a setter.

Answered by user743382

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