Creating entity in database with unmapped property

Question

The entity model I'm working on is structured with inheritence as per:

public abstract class Line {}    
public class WooLine : Line{
   public bool wooProperty{ get; set; }
}

public class BooLine : Line

These are both stored in the database in the table Line. And in the database the column wooProperty is NOT NULL and default value (0).

These are maintained in a web app written with Knockout & Breeze. When working with BooLine trying to create a new entity, it throws an exception that I can't insert NULL into column wooProperty.

I set up a profile to trace the query, and it appears that since it's mapped to the Line table, during the Insert EntityFramework reads up all the properties and tries to actually insert NULL into the wooProperty, since it's not present in the Boo model. I'm moderately upset that EF is actively trying to insert NULL to a property I'm not working with...

Anyway. I can't move the wooProperty to the Line model - it belongs in the WooLine model. I'm hoping to solve it by either modifying the metadata in Breeze or forcing the wooProperty onto the saveChanges data. But I can't get breeze to recognize the property in the metadata. I've tried to run

    metadataStore.registerEntityTypeCtor(
        'BooLine', function () { 
            this.wooProperty = false;
        });

Which almost works - but Breeze maps it as __unmapped value and as such isn't recognized after being recieved by EntityFramework.

I also started playing around with overriding the EFContextProvider and overriding BeforeSaveEntity. Entity is ReadOnly of type BooLine, and I can clearly see WooProperty in the UnmappedProperties, but I have no idea where to go from there... Any ideas?

TLDR in a way; Want to 'trick' entity framework into thinking an unmapped value is mapped when creating an entity.

Answer 1

To summarize my comments I would recommend one of the following:

• make your model use TPT inheritance so there is no wooProperty column in the Line table, but in the inherited WooLine table

• change your wooProperty column to be nullable and mark the wooProperty property in your entity class as [Required] and let EF take care of reading only "valid WooLines" - this should work if there is also a valid discriminator column for EF to use