title: "android.database.sqlite.SQLiteException: no such table" error in rare cases
body: <p>I have an app currently available in the app store, but there is one type of error report that I can't seem to figure out completely. My app uses an internal sqlite database, but on some devices (certainly not the majority) the following error sometimes occurs:</p>
  
  <blockquote>
    <p>android.database.sqlite.SQLiteException: no such table: image_data
    (code 1): , while compiling: SELECT Min(stamp) FROM image_data WHERE
    category = 'Astronomy' AND stamp >= 1357426800 and coalesce(title_nl,
    '') = ''</p>
  </blockquote>
  
  <p>I am sure this table exists and I'm sure this query is correct. I know that this error only occurs in the widgets of the app and in a BroadcastReceiver fired by the AlarmManager (the app once in a while tries to download new entries, as it's a picture of the day app).</p>
  
  <p>I think it has something to do with the Context I am in when accessing the database. I have a class called AppContextHelper which extends Application and has a static member in which I store the context. That context is always used when accessing the database.</p>
  
  <p>My question: could it be that THAT context is invalid in some cases when acquiring the database in a widget or the aforementioned BroadcastReceiver fired by the AlarmManager and that in that case I should use the provided Context in favor of the 'application' context? If so, why is that context invalid or better yet, which context is it that is provided?</p>
  
  <p>Thanks in advance!</p>
  
  <p>As requested the code leading to the problem, again, only on SOME devices and ONLY in the widgets or AlarmManager class. I will post the code leading to the error in the AlarmManager class (that is the code with the least lines)</p>
  
  <ol>
  <li><p>The code initializing the alarm:</p>
  
  <pre><code>    Intent myIntent = new Intent(AppContextHelper.getContext(), ApodDownloader.class);
      mPendingIntent = PendingIntent.getBroadcast(AppContextHelper.getContext(), 0, myIntent, 0);
  
      AlarmManager alarmManager = (AlarmManager)AppContextHelper.getContext().getSystemService(Context.ALARM_SERVICE);
      Calendar calendar = Calendar.getInstance();
      calendar.setTimeInMillis(System.currentTimeMillis());
  
      alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis() + 10000, AlarmManager.INTERVAL_HOUR, mPendingIntent);
  </code></pre></li>
  <li><p>AppContextHelper.java</p>
  
  <pre><code>public class AppContextHelper extends Application {
  
      private static Context mContext;
  
      @Override
      public void onCreate() {
          super.onCreate();
          mContext = this;
      }
  
      public static Context getContext(){
          return mContext;
      }
  }
  </code></pre></li>
  <li><p>(part of) ApodDownloader.java (this contains the line of the exception being thrown)</p>
  
  <pre><code>@Override
  public void onReceive(Context arg0, Intent arg1) {
      (new AsyncTaskThreadPool&lt;Integer, Void, Boolean&gt;() {
  
          @Override
          protected Boolean doInBackground(Integer... params) {
              Helpers.logMessage("Checking new entries.");
  
  
              SQLiteDatabase db = FrescoDatabase.acquireReadableDatabase(AppContextHelper.getContext());
              try {
                  &gt;&gt;&gt; THIS LINE THROWS THE EXCEPTION &lt;&lt;&lt;
                  maxStamp = Helpers.executeScalarLong(db, "SELECT Min(stamp) FROM image_data WHERE category = 'Astronomy' AND stamp &gt;= 1357426800 and coalesce(title_nl, '') = ''");
  
                  [...]
              } finally {
                  FrescoDatabase.releaseReadableDatabase();
              }
  
              [...] more code
  
          }
          [...] onPostExecute
      }).executeOnExecutor(AsyncTaskThreadPool.THREAD_POOL_EXECUTOR, 0);
  </code></pre></li>
  <li><p>FrescoDatabase.java
  The database is automatically generated by the app on startup, this code is working, also on the devices that fire the exception. I cannot emphasize enough that the database exists on the problematic devices, since app is running flawlessly with the exception of the widgets and BroadcastReceiver of the AlarmManager, so please don't tell me the db is not initialized correctly :)</p>
  
  <pre><code>public class FrescoDatabase extends SQLiteOpenHelper {
  
      public static final String[] OBSOLETE_DATABASE_FILE_NAMES = new String[] { "Fresco.v1.sqlite", "Fresco.v2.sqlite", "Fresco.v3.sqlite", "Fresco.v4.sqlite", "Fresco.v5.sqlite" };
      public static final String DATABASE_FILE_NAME = "Fresco.v6.sqlite";
      public  static final int DATABASE_FILE_SIZE = 15302656;
      private static final int DATABASE_VERSION = 7;
  
      private static final Lock writeLock = new ReentrantLock();
      private static SQLiteDatabase currentDB = null;
  
      public static final SQLiteDatabase acquireWritableDatabase(Context c) {
          writeLock.lock();
          currentDB = new FrescoDatabase(c).getWritableDatabase();
          return currentDB;
      }
  
      public static final void releaseWritableDatabase() {
          currentDB.close();
          currentDB = null;
          writeLock.unlock();
      }
  
      public static final SQLiteDatabase acquireReadableDatabase(Context c) {
          writeLock.lock();
          currentDB = new FrescoDatabase(c).getReadableDatabase();
          return currentDB;
      }
  
      public static final void releaseReadableDatabase() {
          currentDB.close();
          currentDB = null;
          writeLock.unlock();
      }
  
      private FrescoDatabase(Context context) {
          super(context, InitializeFrescoDatabaseTask.getDatabaseFileName(context), null, DATABASE_VERSION);
      }
  
      @Override
      public void onCreate(SQLiteDatabase db) {
          // database is automatically generated, this should not be called
      }
  
      @Override
      public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
      }
  }
  </code></pre></li>
  <li><p>(part of) Helpers.java</p>
  
  <pre><code>    public class Helpers {
          [...]
          public static long executeScalarLong(SQLiteDatabase db, String query) {
              return executeScalarLong(db, query, new String[] { });
          }
          public static long executeScalarLong(SQLiteDatabase db, String query, String... parameters) {
              (line 85, see stack trace down below) Cursor cursor = db.rawQuery(query, parameters);
              try {
                  cursor.moveToNext();
                  long val = cursor.getLong(0);
                  return val;
              }   
              catch (Exception e) {
                  ;
              }
              finally {
                  cursor.close();
              }
              return -1;
          }
      }
  </code></pre></li>
  </ol>
  
  <p>The exception log (as requested):</p>
  
  <pre><code>            java.lang.RuntimeException: An error occured while executing doInBackground()
                  at nl.tagpulse.utils.AsyncTaskThreadPool$3.done(AsyncTaskThreadPool.java:329)
                  at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
                  at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
                  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
                  at java.util.concurrent.FutureTask.run(FutureTask.java:137)
                  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
                  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
                  at java.lang.Thread.run(Thread.java:856)
                  Caused by: android.database.sqlite.SQLiteException: no such table: image_data (code 1): , while compiling: SELECT Min(stamp) FROM image_data WHERE category = 'Astronomy' AND stamp &gt;= 1357426800 and coalesce(title_nl, '') = ''
                  at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
                  at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:1012)
                  at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:623)
                  at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
                  at android.database.sqlite.SQLiteProgram.&lt;init&gt;(SQLiteProgram.java:58)
                  at android.database.sqlite.SQLiteQuery.&lt;init&gt;(SQLiteQuery.java:37)
                  at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
                  at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1314)
                  at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1253)
                  at nl.tagpulse.fresco.other.Helpers.executeScalarLong(Helpers.java:85)
                  at nl.tagpulse.fresco.other.Helpers.executeScalarLong(Helpers.java:82)
                  at nl.tagpulse.fresco.business.FrescoDatabase.retrieveNewEntries(FrescoDatabase.java:64)
                  at nl.tagpulse.fresco.business.ApodDownloader$1.doInBackground(ApodDownloader.java:192)
                  at nl.tagpulse.fresco.business.ApodDownloader$1.doInBackground(ApodDownloader.java:1)
                  at nl.tagpulse.utils.AsyncTaskThreadPool$2.call(AsyncTaskThreadPool.java:317)
                  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
                  ... 4 more
  </code></pre>
  
  <p>I added a line 85 marker at the Helpers.java block.</p>
  
  <p>Hope this helps!</p>