为什么我的应用程序在手机上崩溃，但在AVD模拟器上却没有崩溃？

我已经编写了一个使用SQLite db的应用程序。在我不使用SQLite而是仅使用普通字段和普通字段存储数据的第一阶段，我的应用程序在手机中的运行情况就很好。但是现在，当我使用SQLite有效存储和提取数据时，我的应用程序在手机中崩溃了。有趣的一点是，它在我的计算机上的AVD模拟器上运行良好。知道为什么会这样吗？

这是我的数据库类：

public class WordsDB extends SQLiteOpenHelper {

    static final String DATABASE_NAME = "DicDB";

    static final String TermTable = "Terms";
    static final String ID = "id";
    static final String Selected = "selected";
    static final String Term = "term";
    static final String Br = "br_phon";
    static final String NAm = "nam_phon";
    static final String Type = "type";
    static final String Noun = "noun";
    static final String Verb = "verb";
    static final String Adjective = "adjective";
    static final String Adverb = "adverb";

    static final String DefTable = "Definitions";
    static final String Def = "definition";
    static final String Ex = "example";

    public static final int DATABASE_VERSION = 1;

    private static final String TERM_TABLE_CREATE = "Create table " + TermTable +
        "(" + ID + " INTEGER PRIMARY KEY AUTOINCREMENT," +
        Selected + " VARCHAR(5) ," +
        Term + " VARCHAR(20) ," +
        Br + " VARCHAR(20) ," +
        NAm + " VARCHAR(20) ," +
        Type + " VARCHAR(10) ," +
        Noun + " VARCHAR(20) ," +
        Verb + " VARCHAR(20) ," +
        Adjective + " VARCHAR(20) ," +
        Adverb + " VARCHAR(20)) ";

    private static final String DEF_TABLE_CREATE = "Create table " + DefTable +
        "(" + ID + " INTEGER PRIMARY KEY ," +
        Def + " VARCHAR(30) ," +
        Ex + " VARCHAR(160)) ";

    public WordsDB(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db)
    {
    db.execSQL(TERM_TABLE_CREATE);
    db.execSQL(DEF_TABLE_CREATE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
    {
        db.execSQL("DROP TABLE IF EXISTS " + TermTable);
        db.execSQL("DROP TABLE IF EXISTS " + DefTable);
        onCreate(db);
    }
}

这是DataSource类：

public class WordsDS {

    private WordsDB dbHelper;
    private SQLiteDatabase db;

    public WordsDS(Context context) {
        dbHelper = new WordsDB(context);
    }

    public void open() throws SQLException {
        db = dbHelper.getWritableDatabase();
    }

    public void close() {
        db.close();
    }

    // Methods to inset, update and extract data from table
    .......
}

我在主要活动中从WordsDS类中创建一个对象，并通过开放方法获得可写数据库，依此类推；在其他类中，我使用WordsDS对象并通过该对象插入，更新和提取数据。