CoreData - can't set empty string as default value for attribute

Question

I have an entity in my datamodel with a string attribute that is currently optional, and I\'d like to convert this to a required attribute with a default value of the empty stri

Answer 1

Here is the Swift solution based on David Ravetti's answer and edelaney05's comment. In addition, I added optionality check.

This solution works fine in my projects.

class ExampleEntity: NSManagedObject {

    ...

    override func awakeFromInsert() {
        super.awakeFromInsert()
        for (key, attr) in self.entity.attributesByName {
            if attr.attributeType == .stringAttributeType && !attr.isOptional {
                if self.value(forKey: key) == nil {
                    self.setPrimitiveValue("", forKey: key)
                }
            }
        }
    }

    ...
}

Answer 2

A simpler solution based on Scott Marks answer to avoid syntax errors:

First, temporarily set the default value to be easy to find, something like here you are. Open with any text editor the contents file inside the .xcdatamodel bundle inside the .xcdatamodeld bundle. Then just do a search with replacing the string "here you are" with the "" in this file.

The migration took place without problems.