I have an issue where the Sql generated from a Graphql request is using an inner join that is causing data to be skipped. This is because the join is happening on an id field that can be null. I have no control over the id field so I cannot just make the field not-null. I have re-written the Sql exchanging the inner join for a left join and it works as desired but I cannot figure out how to get Hot Chocolate to do the same.
Example of relationship (not actual code being worked with):
public class Person {
public Guid PersonId {get;set;}
public string Name {get;set;}
public Guid CarId {get;set;}
public virtual Car OwnedCar {get;set}
}
public class Car {
public Guid CarId {get;set;}
public string Brand {get;get;}
public virtual ICollection<Person> OwnersOfThisTypeOfCar {get;set;}
}
At the database context I have a many to one relationship set up like
protected override void OnModelCreating(ModelBuilder modelBuilder)
//code omitted for brevity
modelBuilder.Entity<Car>(entity => {
//code omitted for brevity
entity.HasMany(d => d.OwnersOfThisTypeOfCar)
.WithOne(p => p.OwnedCar)
.HasForeignKey(p => p.CarId);
});
when making a Graphql request like:
{person() {name, ownedCar{ brand }}}
I expect to get back all people in the DB and the car they own or null for the car if they don't have one. So I expect the Sql generated to look like
Select t.name, t1.brand from people as t
left join cars as t1 on t.carId = t1.carId;
Instead I get
Select t.name, t1.brand from people as t
inner join cars as t1 on t.carId = t1.carId;
which, of course only returns the people that have cars.
I feel that there is some simple solution that would allow Hot Chocolate to specify that the field / type only be populated when it is not null (thereby informing EfCore to use a left join) but I just can't find it. Any help in this would be greatly appreciated as I have spent quite a few hours trying to figure it out.
