CODEWITHSUNDEEP
core-data
Lefteris
Lefteris

Reputation: 14687

Core Data Model Cascade Delete and Parent Entity

I have a question about the Core Data Model and the Cascade Delete Rule.

My Core Data Model is this one:

Core Data Model

As you can see the User Entity has a "To Many" Relationship with the Orders Entity. Also the Orders Entity has a parent entity called Cuisines, as each Order needs to be from a list of available Cuisines.

The User To Orders Relationship delete Rule is Cascade (the inverse is nullify) as I want all orders to be deleted if the user object is deleted.

My question is what happens with the Cuisines Entity if I delete the User?

The Cuisines should be available for all orders placed for other Users as well, so it must persist. Will it be also deleted?

If yes, how should I create my model and set the delete rules to avoid this?

Upvotes: 1

Views: 288

Answers (1)

pbasdf
pbasdf

Reputation: 21536

Specifying Cuisines as the parent entity for Orders means that each Orders object is a Cuisine - albeit a specific "type" of Cuisine. Each Order has three attributes: numOfOrders, rating and name. When you delete an Order (albeit through a cascade rule), you are deleting one object with all three attributes - there isn't a separate Cuisines object to be deleted.

But you want each order to be from a list of available cuisines. So replace the parent/subentity link between Orders and Cuisines with a relationship. Each Cuisine can be related to several different Orders, so the relationship would be to-many. Conversely, each Order relates to only one Cuisine, so the inverse relationship will be to-one. When you delete an Order, you want the related Cuisines to remain (for use in other Orders) so the delete rule would be "nullify".

Upvotes: 0

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