SQLiteException - occurs only on some devices

Question

I recently published an app on the market. From the developer console, it seems that about 1-2% of my users are faced with this problem. 1-2% are small, but people are more likely to leave comments when something does not work, and not when it happens, which can negatively affect the download.

Unfortunately, the developer console only displays the platform as "different", but my application is available to those who have SDK 1.6+. I also can not recreate this problem, and no user has contacted me directly, so I can not get more information about devices in which it does not work.

Here is the stack

android.database.sqlite.SQLiteException: no such table: QUESTIONS: , while compiling: SELECT * FROM QUESTIONS WHERE DIFFICULTY=2 ORDER BY RANDOM() LIMIT 20 at android.database.sqlite.SQLiteCompiledSql.native_compile(Native Method) at android.database.sqlite.SQLiteCompiledSql.compile(SQLiteCompiledSql.java:91) at android.database.sqlite.SQLiteCompiledSql.<init>(SQLiteCompiledSql.java:64) at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:80) at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:46) at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:53) at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1434) at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1404) at com.app.myapp.db.DBHelper.getQuestionSet(DBHelper.java:140) at com.app.myapp.SplashActivity.getQuestionSetFromDb(SplashActivity.java:109) at com.app.myapp.SplashActivity.onClick(SplashActivity.java:58) at android.view.View.performClick(View.java:2421) at android.view.View$PerformClick.run(View.java:8867) at android.os.Handler.handleCallback(Handler.java:587) at android.os.Handler.dispatchMessage(Handler.java:92) at android.os.Looper.loop(Looper.java:143) at android.app.ActivityThread.main(ActivityThread.java:5068) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:521) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) at dalvik.system.NativeStart.main(Native Method) 

getQuestionSetFromDb (SplashActivity.java:109) refers to

 List<Question> questions = myDbHelper.getQuestionSet(diff, numQuestions); 

What relates to

 public List<Question> getQuestionSet(int difficulty, int numQ){ List<Question> questionSet = new ArrayList<Question>(); Cursor c = myDataBase.rawQuery("SELECT * FROM QUESTIONS WHERE DIFFICULTY=" + difficulty + " ORDER BY RANDOM() LIMIT " + numQ, null); while (c.moveToNext()){ //Log.d("QUESTION", "Question Found in DB: " + c.getString(1)); Question q = new Question(); q.setQuestion(c.getString(1)); q.setAnswer(c.getString(2)); q.setOption1(c.getString(3)); q.setOption2(c.getString(4)); q.setOption3(c.getString(5)); q.setRating(difficulty); questionSet.add(q); } return questionSet; } 

}

Does anyone know a likely cause? It is strange that this happens only with a small number of installations and the inability to determine the level or SDK device that they use makes it difficult.

Any help is appreciated

EDIT: Due to the answers, I include how db is created.

Firstly, my activity has this (this is the same method that causes the crash)

  private List<Question> getQuestionSetFromDb() throws Error { int diff = getDifficultySettings(); int numQuestions = getNumQuestions(); DBHelper myDbHelper = new DBHelper(this); try { myDbHelper.createDataBase(); } catch (IOException ioe) { throw new Error("Unable to create database"); } try { myDbHelper.openDataBase(); }catch(SQLException sqle){ throw sqle; } List<Question> questions = myDbHelper.getQuestionSet(diff, numQuestions); myDbHelper.close(); return questions; } 

myDBhelper.createdatabase () calls

 public void createDataBase() throws IOException{ boolean dbExist = checkDataBase(); if(!dbExist) { //By calling this method and empty database will be created into the default system path //of your application so we are gonna be able to overwrite that database with our database. this.getReadableDatabase(); try { copyDataBase(); } catch (IOException e) { throw new Error("Error copying database"); } } } 

checkDatabase ()

  private boolean checkDataBase(){ SQLiteDatabase checkDB = null; try{ String myPath = DB_PATH + DB_NAME; checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); }catch(SQLiteException e){ //database does't exist yet. } if(checkDB != null){ checkDB.close(); } return checkDB != null ? true : false; } 

copyDatabase ()

  private void copyDataBase() throws IOException{ //Open your local db as the input stream InputStream myInput = myContext.getAssets().open(DB_NAME); // Path to the just created empty db String outFileName = DB_PATH + DB_NAME; //Open the empty db as the output stream OutputStream myOutput = new FileOutputStream(outFileName); //transfer bytes from the inputfile to the outputfile byte[] buffer = new byte[1024]; int length; while ((length = myInput.read(buffer))>0){ myOutput.write(buffer, 0, length); } //Close the streams myOutput.flush(); myOutput.close(); myInput.close(); } 

Variables

  private static String DB_PATH = "/data/data/com.app.myapp/databases/"; private static String DB_NAME = "questionsDb"; private SQLiteDatabase myDataBase; private final Context myContext; 

Apoliticians, I really should have included this initially

Answer 1

The error message contains information about the missing QUESTIONS database. DB_NAME - "questionsDb".

The int complexity added with + to the line also puzzles me (it was already reported from another user earlier in this thread).

Answer 2

I just feel like you are creating a database causing a problem. There is nothing wrong; as you said, it works on 98% of devices.

In my opinion, you are probably better off extending SQLiteOpenHelper . This will help to create your database if it does not exist, and you do not need to do any checks manually.