Question

I am making an app in which i need that the rows that were inserted in the tables should get deleted on click of a button when the activity restarts.

I have tried the following approaches but didnot get the desired result and the same rows get inserted again.

public void deleteDatabase(String databaseName) {
        context.deleteDatabase(databaseName);

    }

and

       public void deleteAll(){
           db.execSQL("TRUNCATE TABLE" +DATABASE_TABLE);
           db.execSQL("TRUNCATE TABLE" +DATABASE_TABLE_ICOn);
           db.execSQL("TRUNCATE TABLE" +DATABASE_TABLE_NAVIGATION);
           this.db.delete(DATABASE_TABLE, null, null);
           this.db.delete(DATABASE_TABLE_NAVIGATION,null, null);
           this.db.delete(DATABASE_TABLE_ICOn, null, null);
       }



      db = new WineDatabaseAdapter(HomePageWithPhoneIsOfflineDialog.this);

    final AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setMessage("Your Phone is Offline")
            .setCancelable(false)
            .setPositiveButton("Go Online",
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog1, int id1) {

                            if(WineDatabaseHelper.checkDataBase()==true){

                                db.deleteDatabase(WineDatabaseHelper.DATABASE_NAME);
                                //db.deleteAll();
                            }

What shall i do to solve my problem.
Thanks

Answer 1

Truncate is not supported by Sqlite so its better to use DELETE

The standard way to delete all the rows in a SQL

DELETE FROM MyTable

You can also execute VACUUM to compact the database when you are deleting lot of data and want to shrink the database file.