CODEWITHSUNDEEP
swiftsqlitensdate
user5218750
user5218750

Reputation:

NSDate variable as nil

An init method for Person class looks like 

init (id:int64, firstName:String, lastName:String, birthDay:NSDate?)

As you can see birthDay is an optional, because we don't always have the birthday.

The data comes from a SQLite database. A date type does not exist in SQLite so the date is represented as a string (which can be NULL). To convert that string to an NSDate I created an extension to NSDate :

extension NSDate: Value {
    public class var declaredDatatype: String {
        return String.declaredDatatype
    }
    public class func fromDatatypeValue(stringValue: String) -> NSDate {
        return SQLDateFormatter.dateFromString(stringValue)!
    }
    public var datatypeValue: String {
        return SQLDateFormatter.stringFromDate(self)
    }
}

So when creating a person: 

let person = Person(id: row[id], firstName: row[first_name], lastName: row[last_name], birthDay:NSDate.fromDatatypeValue(row[birthday]!))

will fail if the birthday string is NULL. (I have to unwrap the row[birthday]! as expects a non-optional String, and this may/can not be changed)

So my idea was to test for this before creating the person

 var birthday : NSDate
            if let birthdayString = row[Person.birthday] {
                birthday = NSDate.fromDatatypeValue(birthdayString)
            } else {
                birthday=nil
            }

and the use birthday in the init function.

BUT swift tells me : Cannot assign a value of type 'nil' to a value of 'NSDate'

How can this be solved ?

PS. : I know I could have an if and 2 initializers but I'd rather not have as my Person init func has 12 parameters (for reasons of simplicity I've only used 4 above) and maintaining this is a pita

Upvotes: 4

Views: 6114

Answers (1)

Joe
Joe

Reputation: 2452

Do the following.

var birthday : NSDate? = nil
if let birthdayString = row[Person.birthday] {
    birthday = NSDate.fromDatatypeValue(birthdayString)
}

Upvotes: 8

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