SQLiteDatabase db, ch

mHelper = new WordDBHelper(this);

datech = new DateChecker(this);

db = mHelper.getReadableDatabase();

        Cursor cursor;

        cursor = db.rawQuery("SELECT * FROM word", null);

        while(cursor.moveToNext()){

        words.add(cursor.getString(0));

        means.add(cursor.getString(1));

        }

        cursor.close();

        db.close();

ch = datech.getReadableDatabase();         <--여기서 에러가 납니다... 이거만 참조로 바꾸면 에러가 안나고 실행됩니다..

각각의 openhelper는 다음과 같습니다.

class WordDBHelper extends SQLiteOpenHelper{

public WordDBHelper(Context context){

super(context, "word.db", null, 1);

}

@Override

public void onCreate(SQLiteDatabase db) {

db.execSQL("CREATE TABLE word(word_spell VARCHAR(15) PRIMARY KEY," + " word_mean VARCHAR(10) NOT NULL);");

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

db.execSQL("DROP TABLE IF EXISTS word");

onCreate(db);

}

}

class DateChecker extends SQLiteOpenHelper{

public DateChecker(Context context){

super(context, "date.db", null, 1);

}

@Override

public void onCreate(SQLiteDatabase db) {

db.execSQL("CREATE TABLE date(day INT NOT NULL," + " month INT NOT NULL," + " year INT NOT NULL," + " index INT PRIMARY KEY);");

}

@Override

public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

db.execSQL("DROP TABLE IF EXISTS date");

onCreate(db);

}

}

WordDBHelper랑 DateChecker랑 똑같이 쓴 거 같은데, 왜 위에꺼는 에러가 안나고 밑에꺼만 실행이 되지 않는지 모르겠습니다;;

도와주세요~!!