未创建数据库在我的代码中

Question

这是我的代码。此代码不会按预期创建数据库。 有人能指出这段代码中有什么问题吗？

    public class DataBaseHelper extends SQLiteOpenHelper {
        private static final int DATABASE_VERSION = 1;
        private static final String DATABASE_NAME = "contactsManager";
        private static final String TABLE_CONTACTS = "contacts";            
        private static final String KEY_ID = "id";
        private static final String KEY_NAME = "name";
        private static final String KEY_PH_NO = "phone_number";            
        public DataBaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }
        @Override
        public void onCreate(SQLiteDatabase db) {
            String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "(" + KEY_ID + " INTEGER PRIMARY KEY,"
                    + KEY_NAME + " TEXT," + KEY_PH_NO + " TEXT" + ")";
            db.execSQL(CREATE_CONTACTS_TABLE);
        }
        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            db.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACTS);
            onCreate(db);
        }
    }