I am trying to create a `NSMutableArray` and add dictionary values from db (using fm db result set) then I got this error:

```
"fatal error: unexpectedly found nil while unwrapping an Optional value ".

```

Please give tips to solve this issue.

Code:

```
var arrCategory :NSMutableArray!

while rs.next(){

    arrCategory.addObject(rs.resultDictionary())
}

```