How to create MPMediaItem from assetURL!.absoluteString?

I am saving (mediaItemCollection.items.first?.assetURL!.absoluteString) to local SQLite DB as String. Now I want to create MPMediaItem object back from saved string i.e assetURL!.absoluteString, Is it possible to create MPMediaItem object from its assesURL? If it is not possible then what should I save to SQLite DB so that I can create object of MPMediaItem back from saved property?

I have find the solution from @user28434 suggestion.

I am saving persistentID to SQLite DB as String

 let songItem = mediaItemCollection.representativeItem!
 let persistantID = String(songItem.persistentID)

From this persistentID I am able to create MPMediaItem object back using MPMediaQuery while fetching stored persistentID from DB.

Following way to create MPMediaItem object.

 let noCloudPre = MPMediaPropertyPredicate(value: NSNumber(booleanLiteral: false),
                                              forProperty: MPMediaItemPropertyIsCloudItem)

    func getSongItem(persistantID: String) -> MPMediaItem?{
        let songQuery = MPMediaQuery.songs()
        songQuery.addFilterPredicate(noCloudPre)
        songQuery.addFilterPredicate(MPMediaPropertyPredicate(value: persistantID,
                                    forProperty: MPMediaItemPropertyPersistentID,
                                    comparisonType: MPMediaPredicateComparison.equalTo))
        return songQuery.items?[0]
    }