Cordova SQL code does not work

Question









   
   

   Embedded Sql Example


    


WebSQL



 



Currently stored values:

from logcat:

E/Web Console(21030): Uncaught ReferenceError: AddValueToDB is not defined:204
E/DataRouter(  154): Opening of the USB File failed fd is -1 & errno is 2

The code above is widely cited when searching for cordova/phonegap sql examples. For me it does not work. No error messages are thrown by the app's alerts, and logcat complains that functions defined in the source are unknown. I'm using cordova/phonegap 3.1.0 from the cli. The app runs on a Samsung SGS2/Android 4.1.2. Why does this demo app not work?

aharris88 · Accepted Answer

I believe the problem is with the body onload="onbodyLoad()". With phonegap, you have to make sure that the device is actually ready using an eventlistener for the deviceready event. Here is the code that I got working. Make sure you have downloaded and included jquery. I'm using version 1.7.2. I also separated the javascript into a separate file so that I could use jslint to debug it. I also changed the doctype to html 5.

Index.html:




    Embedded Sql Example
    
    

    

    
    
    


    WebSQL
    
    
    
     

    

    Currently stored values:

Index.js:

var app = {
  // Application Constructor
  initialize: function() {
    this.bindEvents();
  },
  // Bind Event Listeners
  //
  // Bind any events that are required on startup. Common events are:
  // 'load', 'deviceready', 'offline', and 'online'.
  bindEvents: function() {
    document.addEventListener('deviceready', this.onDeviceReady, false);
  },
  // deviceready Event Handler
  //
  // The scope of 'this' is the event. In order to call the 'receivedEvent'
  // function, we must explicity call 'app.receivedEvent(...);'
  onDeviceReady: function() {
    onBodyLoad();
  },
};


// global variables
var db;
var shortName = 'WebSqlDB';
var version = '1.0';
var displayName = 'WebSqlDB';
var maxSize = 65535;

// this is called when an error happens in a transaction
function errorHandler(transaction, error) {
  alert('Error: ' + error.message + ' code: ' + error.code);
}

// this is called when a successful transaction happens
function successCallBack() {
  alert("DEBUGGING: success");
}

function nullHandler() {}

// called when the application loads
function onBodyLoad() {
  // This alert is used to make sure the application is loaded correctly
  // you can comment this out once you have the application working
  alert("DEBUGGING: we are in the onBodyLoad() function");

  if (!window.openDatabase) {
    // not all mobile devices support databases  if it does not, the following alert will display
    // indicating the device will not be albe to run this application
    alert('Databases are not supported in this browser.');
    return;
  }

  // this line tries to open the database base locally on the device
  // if it does not exist, it will create it and return a database object stored in variable db
  db = openDatabase(shortName, version, displayName,maxSize);

  // this line will try to create the table User in the database just created/openned
  db.transaction(function(tx){

  // you can uncomment this next line if you want the User table to be empty each time the application runs
  // tx.executeSql( 'DROP TABLE User',nullHandler,nullHandler);

  // this line actually creates the table User if it does not exist and sets up the three columns and their types
  // note the UserId column is an auto incrementing column which is useful if you want to pull back distinct rows
  // easily from the table.
  tx.executeSql( 'CREATE TABLE IF NOT EXISTS User(UserId INTEGER NOT NULL PRIMARY KEY, FirstName TEXT NOT NULL, LastName TEXT NOT NULL)',
    [], nullHandler, errorHandler);
    }, errorHandler, successCallBack);
}


// list the values in the database to the screen using jquery to update the #lbUsers element
function ListDBValues() {
  if (!window.openDatabase) {
    alert('Databases are not supported in this browser.');
    return;
  }


  // this line clears out any content in the #lbUsers element on the page so that the next few lines will show updated
  // content and not just keep repeating lines
  $('#lbUsers').html('');

  // this next section will select all the content from the User table and then go through it row by row
  // appending the UserId  FirstName  LastName to the  #lbUsers element on the page
  db.transaction(function(transaction) {
    transaction.executeSql('SELECT * FROM User;', [],
    function(transaction, result) {
      if (result !== null && result.rows !== null) {
        for (var i = 0; i < result.rows.length; i++) {
          var row = result.rows.item(i);
          $('#lbUsers').append('
' + row.UserId + '. ' + row.FirstName+ ' ' + row.LastName);
        }
      }
    }, errorHandler);
  }, errorHandler, nullHandler);
  return;
}

// this is the function that puts values into the database using the values from the text boxes on the screen
function AddValueToDB() {
  if (!window.openDatabase) {
    alert('Databases are not supported in this browser.');
    return;
  }

  // this is the section that actually inserts the values into the User table
  db.transaction(function(transaction) {
    transaction.executeSql('INSERT INTO User(FirstName, LastName) VALUES (?,?)',[$('#txFirstName').val(), $('#txLastName').val()],
    nullHandler, errorHandler);
  });

  // this calls the function that will show what is in the User table in the database
  ListDBValues();

  return false;
}
/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

Cordova SQL code does not work

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