swift : How to get back the object from a String

for the iOS app I am currently working on I need to fetch data from my server, as the server is taking more time than I expected I stored the JSON data and the cookies in an SQLite DB(I am using the library FMDB for this purpose) obtained by the app during the previous launching of app. As SQLite doesn't allow SwiftyJSON objects to be passed, I am doing a string interpolation to send it as TEXT. I know I can tokenise the string and build the JSON object as well as the cookies but I was wondering if there was any method I can use to convert a string to the object directly. Is there such a method or some hack I can use to get it? Any help is appreciated