Opening and using a database from another view controller

Question

I have created a database in one view controller and I would like to open it and access it in another view controller. I was wondering how to open up a existing database from one view controller in another view controller. I intend to open up the database and be able to update a row, so I would also need access to the "parts" (ex. id, name, email). Could you help me? Anything would be helpful. Thanks!

Answer 1

You can access your DB from any VC. Code (which you will probably use anywhere you want to access your DB from) would be like

let path = NSSearchPathForDirectoriesInDomains(
            .documentDirectory, .userDomainMask, true
        ).first!

do {
                let db = try Connection("\(path)/<your.db.filename>")

                let recordsTable = Table("records")
                //or whatever you'd like to do, extract, modify, insert or delete

    } 
catch let error {
            print("Data operation failed for records table: \(error)")
        }

Instead of copying same code all over your project, you can separately create your own class for any of your DB operations and access it from anywhere:

    class DatabaseOps {
    //..
    func getHighscoreTable() -> Array<HighScoreDataArray> {
                
            let path = NSSearchPathForDirectoriesInDomains(
                .documentDirectory, .userDomainMask, true
            ).first!
            
            var highscores = [HighScoreDataArray]()
                
                do {
                    let db = try Connection("\(path)/tasksolver.db")
    
                    let score = Expression<Int>("Score")
                    let username = Expression<String>("Username")
                    let recordsTable = Table("records").order(score.desc).limit(10)
                    
                        for row in try db.prepare(recordsTable) {
                   
                            let highscore = HighScoreDataArray(score: Int(row[score]), username: String(row[username]))
                            highscores += [highscore]
                        }
                    
                    }     catch let error {
                    print("Data operation failed for records table: \(error)")
                }
    return highscores
        }

//..
}

    class RecordsViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
    
    var myDb : DatabaseOps = DatabaseOps()
    //...
    super.viewDidLoad()
    //get the data from database by using myDB method
    myHighScoreTable = myDb.getHighscoreTable()

Also, before you try it in different VCs - don't forget to make sure you have your DB file in place. If it is not, let db = try Connection will create an empty database for you, which will not contain any of your data or tables you want to access.