How to handle resultDictionary nulls in swift?

Question

With FMDB resultset's resultDictionary method returns a dictionary for each row where the keys are the column names which have a value or are NSNulls. So I am trying to figure out how best to handle these and where.

So with the new update of swift I need to change my code and in the process I am looking at some refactoring.

So as it stands the following line of code's "as" needs to be made to "as?" or "as!" :

resultsArray.append(resultSet.resultDictionary() as Dictionary<String,AnyObject>)

Robert stated I should handle them like this. But it got me thinking about a better solution and thus I am looking for some advice on how I should refactor:

I could get the optional, find nulls and replace the NSNulls with empty string literals "" and this handle empty strings somewhere else in my app.
I could just leave them as is and force unwrap.

public class func queryGetAllRowsFromTableAsArrayOfHashes() -> Array<Dictionary<String,AnyObject>>? {

var resultsArray = Array<Dictionary<String,AnyObject>>()
let database = DBUtility.getDatabaseHandle()

//Perform query and place result into a dictionary.
self.log().info("Getting all rows from: \(self.getTableName())")
if let resultSet = database.executeQuery(self.getAllRowsStatement()) {
    self.log().info("Query run")
    while resultSet.next() {
        //adds a dictionary of the result row to the array.
        resultsArray.append(resultSet.resultDictionary() as! Dictionary<String,AnyObject>)
    }
    self.log().info("Results array: \(resultsArray)")
    return resultsArray;
}else{
   self.log().error("DB Error: \(database.lastErrorMessage())")
}
return nil;
}

Anyone got some advice on where this should be tackled?

score 1 · Answer 1 · answered May 11 '15 at 13:28

1

You can simply put a check in if statement like this

if var dict = resultSet.resultDictionary() as Dictionary<String,AnyObject> 
{
  resultsArray.append(resultSet.resultDictionary() as! Dictionary<String,AnyObject>)
}

It will only append the value in array if there is non null value. hope it will help you.If value is null then if statement will not be executed.

answered May 11 '15 at 13:28

Krishna Verma

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But it is not the dictionary that is null.. just some of the contents.. eg "address" -> NSNull – Nate Uni May 11 '15 at 13:43
In these case you need to do the same when you access elements in the dict like "address" – Krishna Verma May 11 '15 at 13:48
when ever you fetch the value from the resultsArray you need to put the same check for all the fields which might be nil. – Krishna Verma May 11 '15 at 13:52

How to handle resultDictionary nulls in swift?

1 Answers1