Why individual delete calls with delete on cascade

[kussaued]

I've got two tables with an 1:n relation and a delete on cascade in my database:

Code: Select all

CREATE TABLE animals (
	Id				INTEGER			PRIMARY KEY	AUTO_INCREMENT,
	Description		VARCHAR(512),
	Timestamp		TIMESTAMP 		DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);

CREATE TABLE animal_events (
	Id				INTEGER			PRIMARY KEY	AUTO_INCREMENT,
	Begin			DATETIME		NOT NULL,
	AnimalId		INT,
	Timestamp		TIMESTAMP 		DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
	FOREIGN KEY animal_fk(AnimalId) REFERENCES animals(Id) ON DELETE CASCADE
);

So when I delete an animal, all the corresponding animal_events should be deleted also.
This is something that is done by the database, triggered by the delete on cascade clause whenever I delete an animal. Correct?

But in the sql trace I see many individual delete commands. Why is the entity framework/devart doing this?

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DELETE FROM rfidfarm.animal_events WHERE Id = 1
DELETE FROM rfidfarm.animal_events WHERE Id = 2
DELETE FROM rfidfarm.animal_events WHERE Id = 3
...

Isn't this superfluous, since the database would take care of it?

My test code:

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using (var uow = _modelFactory.CreateUnitOfWork())
{
    var animal = uow.Animals.GetById(2);
    var animalEventCount = animal.AnimalEvents.Count;
    uow.Animals.Delete(animal);
    uow.SaveChanges();
}

[Shalex]

It is EF engine (designed by Microsoft) which creates the list of operations to be executed. EF provider translates these operations to the database specific SQL statements. We cannot control the logic of operations.