[Michael]

Hi

 

I’m sure this is a noob issue. I’m loading words into Storage (read/parsed from a data file), so I presume once I set a value there (using setValue) that it becomes persistent (i.e. next time, I run the data is available) but when I run the following test on my Windows PC, I never get persistent storage, i.e. I have to reload upon each build/run. Please let me know where i’ve gone wrong. Thanks. BTW I will persue the better ways in future, but this first step is just to help me along with some basic understandings.

import VPlay 1.0
import QtQuick 1.1

GameWindow {
    activeScene: scene
    width: 960; height: 640

    property string loadStatus: "load failed"

    Storage {
      id: myLocalStorage
//      databaseName: "words"

      onStorageError: {
        console.debug("myLocalStorage: there was an error:", errorData.message)
      }
    }

    Component.onCompleted: {

      var isFirstStartApplication = myLocalStorage.getValue("ZEBRA")

      if (isFirstStartApplication == undefined) {

          // if undefined is returned, load up database

          var storageData = fileUtils.readFile("files/dictionary.txt")

          if (storageData) {

              loadStatus = "loaded OK!"

              var arr = storageData.split(",");
              console.debug("words read = " + arr.length)
              loadStatus = "words read = " + arr.length

              // parse cvs file to populate storage

              var obj = {};
              for (var i = 0; i < arr.length - 1; i += 1) {
                  myLocalStorage.setValue(arr[i + 1], true)
              }

          } else {
              loadStatus = "loaded failure!"
              console.debug("loaded file FAILED")
          }

        }

    }

    Scene {
        id: scene
        width: 480; height: 320

        Text { // notification
            id: status
            text: loadStatus
            anchors.centerIn: parent
            color: "white"
        }

        Rectangle {
            id: rectangle
            color: "grey"
            width: 100; height: 50

            Text {
                id: textElement
                text: qsTr("Lookup word")
                color: "#ffffff"
                anchors.centerIn: parent
            }

            MouseArea {
                anchors.fill: parent
                onPressed: {

                    if (myLocalStorage.getValue("ZEBRA")) {
                        status.text = "word found!"
                    }
                    else {
                        status.text = "word NOT found!"
                    }

                }

            }
        }
    }
}

 

[ChristianFelgo Team]

Hi Michael,

the problem here is not the storage persistence, but the readFile function. As I do not have your file contents I cannot reproduce the problem – but you can test it without the file reading, if ou just call something like the following in onCompleted:

myLocalStorage.setValue("ZEBRA", "abc")

If you did that, you will also see that your else-branch should be one colon behind, like in this modified version:

var isFirstStartApplication = myLocalStorage.getValue("ZEBRA")

      if (isFirstStartApplication == undefined) {

          // if undefined is returned, load up database

          var storageData = fileUtils.readFile("files/dictionary.txt")

          if (storageData) {

              loadStatus = "loaded OK!"

              var arr = storageData.split(",");
              console.debug("words read = " + arr.length)
              loadStatus = "words read = " + arr.length

              // parse cvs file to populate storage

              var obj = {};
              for (var i = 0; i < arr.length - 1; i += 1) {
                  myLocalStorage.setValue(arr[i + 1], true)
              }

          } /* DONT put the else branch here, but in the following position
          else {
              loadStatus = "loaded failure!"
              console.debug("loaded file FAILED")
          }*/

        } else {
          loadStatus = "loaded failure!"
          console.debug("loaded file FAILED")
        }
        
      }// end of onCompleted

Cheers, Chris

 

 

 

[Michael]

Thanks alot for your help. I’ve realised the issue. I’ve found often that not all my words are being stored in the sqlite file. Since I’m testing isFirstStartApplication using a word that is near the end of my word list, that word is sometimes not stored or present in the database, so it fails causing the reload. I’ve had a look in the sqlite database and noticed my all my words from the start are being stored to a point, but not all the words. I repeated this test exercise using

var isFirstStartApplication = myLocalStorage.getValue("AA")

where AA is the first word read in & stored, and the persistent test is passed, i.e. words were saved, and things are better.

However as an exercise, when I truncated my word list to 126 words & use the following to populate the sqlite db

for (var i = 0; i < arr.length; i += 1) {
  myLocalStorage.setValue(arr[i], true)
}

sometimes all the words make it, but sometimes not. Why is that?

I guess this loop is not the best method, and I should use the json file method.

Cheers,

Michael.

 

[Michael]

I’ve done a lot of testing, and moved to reading the data, then using JSON.parse, but unless there is some effecient JSON to storage conversion routine, I’ve realised my issue. After parsing the JSON to an obj, I’m looping through the object one by one to populate the local storage one by one using setValue. It’s too slow. I’ve realised that I’m quiting the test app before all the data has been written. This is my issue. I think it’s impractical to use this method to prepare a large database.

[ChristianFelgo Team]

Hi Michael,

you are right. In your case (and especially as you are not writing any new words), using a read-only map is the best solution.

Alternatively, you can add your own SQL database logic and only call a single write transaction which will give you the best performance for your scenario.

Cheers, Chris