Question

I have category entity and subcategory entity. I need to get subcategory data to that related categoryId of category entity.

My category entity contains these attributes: “categoryId”,”categoryName”

subcategory contains: “subcategoryId”,”subcategoryName”, “categoryId”.

So can any one please guide me how can i put the relationship between this two entity ??

Thanks for advance.

Answer 1

Very first you are mixing the concepts of MySQL or SQLite with Core data. Unlike them Core Data does not have primary-foreign Key concept to relate entities(for easy understanding tables in MySQL). Just create relationship between those entities and you can fetch data their data.

Now about your Entities you have are category and subcategory. So you have to create relationship between them. If one category have many subcategories you have to check To many relationship option from Data Model Inspector..Otherwise One to One relationship would be the one you should go for..Have a look at screenshot how you can make your relationship one to many..

This is a good tutorial link for one to many relationship. You can refer if you do not know how to implement.

Also this for tutorial simple relationship in Core Data..

if you are beginner with Core data you can go with Quick Tutorial Start by Apple and you will get basic idea of Core data.