title: How can I clear an SQLite database each time I start my application?
body: <p>I want my SQLite database instance to be wiped away when the program starts.</p>
  
  <p>What I tried was make a method on my class MyDBAdapter.java like this:</p>
  
  <pre><code>public class MyDbAdapter {
      private static final String TAG = "NotesDbAdapter";
      private DatabaseHelper mDbHelper;
      private SQLiteDatabase mDb;
      private static final String DATABASE_NAME = "gpslocdb";
      private static final String PERMISSION_TABLE_CREATE = "CREATE TABLE permission ( fk_email1 varchar, fk_email2 varchar, validated tinyint, hour1 time default '08:00:00', hour2 time default '20:00:00', date1 date, date2 date, weekend tinyint default '0', fk_type varchar, PRIMARY KEY  (fk_email1,fk_email2))";
      private static final String USER_TABLE_CREATE = "CREATE TABLE user ( email varchar, password varchar, fullName varchar, mobilePhone varchar, mobileOperatingSystem varchar, PRIMARY KEY  (email))";
  
      private static final int DATABASE_VERSION = 2;
      private final Context mCtx;
      private static class DatabaseHelper extends SQLiteOpenHelper {
  
          DatabaseHelper(Context context) {
              super(context, DATABASE_NAME, null, DATABASE_VERSION);
          }
  
          @Override
          public void onCreate(SQLiteDatabase db) {
              db.execSQL(PERMISSION_TABLE_CREATE);
              db.execSQL(USER_TABLE_CREATE);
          }
  
          @Override
          public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
              db.execSQL("DROP TABLE IF EXISTS user");
              db.execSQL("DROP TABLE IF EXISTS permission");
              onCreate(db);
          }
      }
  
      /**
       * Constructor - takes the context to allow the database to be
       * opened/created
       * 
       * @param ctx the Context within which to work
       */
      public MyDbAdapter(Context ctx) {
          this.mCtx = ctx;
      }
  
      /**
       * Open the database. If it cannot be opened, try to create a new
       * instance of the database. If it cannot be created, throw an exception to
       * signal the failure
       * 
       * @return this (self reference, allowing this to be chained in an
       *         initialization call)
       * @throws SQLException if the database could be neither opened or created
       */
      public MyDbAdapter open() throws SQLException {
          mDbHelper = new DatabaseHelper(mCtx);
          mDb = mDbHelper.getWritableDatabase();
          return this;
      }
  
      public void close() {
          mDbHelper.close();
      }
  
      public long createUser(String email, String password, String fullName, String mobilePhone, String mobileOperatingSystem) 
      {
          ContentValues initialValues = new ContentValues();
          initialValues.put("email",email);
          initialValues.put("password",password);
          initialValues.put("fullName",fullName);
          initialValues.put("mobilePhone",mobilePhone);
          initialValues.put("mobileOperatingSystem",mobileOperatingSystem);
          return mDb.insert("user", null, initialValues);
      }
  
  
      public Cursor fetchAllUsers() {
  
          return mDb.query("user", new String[] {"email", "password", "fullName", "mobilePhone", "mobileOperatingSystem"}, null, null, null, null, null);
      }
  
      public Cursor fetchUser(String email) throws SQLException {
  
          Cursor mCursor = mDb.query(true, "user", new String[] {"email", "password", "fullName", "mobilePhone", "mobileOperatingSystem"}
              , "email" + "=" + email, null, null, null, null, null);
          if (mCursor != null) {
              mCursor.moveToFirst();
          }
          return mCursor;
      }
      public List&lt;Friend&gt; retrieveAllUsers() 
      {
          List &lt;Friend&gt; friends=new ArrayList&lt;Friend&gt;();
  
          Cursor result=fetchAllUsers();
  
          if( result.moveToFirst() ){
              do{
                  //note.getString(note.getColumnIndexOrThrow(NotesDbAdapter.KEY_TITLE)));
                  friends.add(new Friend(result.getString(result.getColumnIndexOrThrow("email")), "","","",""));
              }while( result.moveToNext() );
          }
  
  
          return friends;
      }
  
  }
  </code></pre>
  
  <p>What is the best way to do this?</p>