安卓：SQLite數據庫

Question

我有這樣的錯誤：

12-07 15:27:11.567: E/AndroidRuntime(15797): Caused by: android.database.sqlite.SQLiteException: no such column: recipient: , while compiling: SELECT _id, recipient, body FROM notes 

我不知道有什麼問題就。我試圖通過點擊發送按鈕將數據保存到數據庫，數據將自動保存到數據庫，並將通過列表視圖顯示在選項卡活動下，但隨後出現此錯誤。這是我的數據庫代碼：

public class MessagesDBAdapter { 

    public static final String KEY_RECIPIENT = "recipient"; 
    public static final String KEY_MESSAGE = "message"; 
    public static final String KEY_ROWID = "_id"; 

    private static final String TAG = "MessagesDBAdapter"; 
    private DatabaseHelper mDbHelper; 
    private SQLiteDatabase mDb; 


    //Database creation sql statement 

    private static final String DATABASE_CREATE = 
     "create table notes (_id integer primary key autoincrement, " 
     + "title text not null, body text not null);"; 

    private static final String DATABASE_NAME = "data"; 
    private static final String DATABASE_TABLE = "notes"; 
    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(DATABASE_CREATE); 
     } 

     @Override 
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
      Log.w(TAG, "Upgrading database from version " + oldVersion + " to " 
        + newVersion + ", which will destroy all old data"); 
      db.execSQL("DROP TABLE IF EXISTS notes"); 
      onCreate(db); 
     } 
    } 

    /** 
    * Constructor - takes the context to allow the database to be 
    * opened/created 
    * 
    * @param ctx the Context within which to work 
    */ 
    public MessagesDBAdapter(Context ctx) { 
     this.mCtx = ctx; 
    } 

    public MessagesDBAdapter open() throws SQLException { 
     mDbHelper = new DatabaseHelper(mCtx); 
     mDb = mDbHelper.getWritableDatabase(); 
     return this; 
    } 

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

    public long createNote(String phoneNo, String message) { 
     ContentValues initialValues = new ContentValues(); 
     initialValues.put(KEY_RECIPIENT, phoneNo); 
     initialValues.put(KEY_MESSAGE, message); 

     open(); 

     return mDb.insert(DATABASE_TABLE, null, initialValues); 
    } 

    public boolean deleteNote(long rowId) { 

     return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0; 
    } 

    public Cursor fetchAllNotes() { 

     return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_RECIPIENT, 
       KEY_MESSAGE}, null, null, null, null, null); 
    } 

    public Cursor fetchNote(long rowId) throws SQLException { 

     Cursor mCursor = 

      mDb.query(true, DATABASE_TABLE, new String[] {KEY_ROWID, 
        KEY_RECIPIENT, KEY_MESSAGE}, KEY_ROWID + "=" + rowId, null, 
        null, null, null, null); 
     if (mCursor != null) { 
      mCursor.moveToFirst(); 
     } 
     return mCursor; 

    } 

    public boolean updateNote(long rowId, String phoneNo, String message) { 
     ContentValues args = new ContentValues(); 
     args.put(KEY_RECIPIENT, phoneNo); 
     args.put(KEY_MESSAGE, message); 

     return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0; 
    } 
} 

任何人都可以幫助我嗎？

這裏的日誌貓錯誤：

12-07 16:10:23.797: E/AndroidRuntime(16596): FATAL EXCEPTION: main 
12-07 16:10:23.797: E/AndroidRuntime(16596): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.KAHTextApp/com.example.KAHTextApp.KAHTextApp}: java.lang.NullPointerException 
12-07 16:10:23.797: E/AndroidRuntime(16596): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at android.app.ActivityThread.access$2300(ActivityThread.java:125) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at android.os.Handler.dispatchMessage(Handler.java:99) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at android.os.Looper.loop(Looper.java:123) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at android.app.ActivityThread.main(ActivityThread.java:4627) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at java.lang.reflect.Method.invokeNative(Native Method) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at java.lang.reflect.Method.invoke(Method.java:521) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at dalvik.system.NativeStart.main(Native Method) 
12-07 16:10:23.797: E/AndroidRuntime(16596): Caused by: java.lang.NullPointerException 
12-07 16:10:23.797: E/AndroidRuntime(16596): at com.example.KAHTextApp.MessagesDBAdapter.fetchNote(MessagesDBAdapter.java:98) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at com.example.KAHTextApp.KAHTextApp.populateFields(KAHTextApp.java:190) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at com.example.KAHTextApp.KAHTextApp.onCreate(KAHTextApp.java:68) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
12-07 16:10:23.797: E/AndroidRuntime(16596): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 

Answer 1

那麼，你的SELECT查詢嘗試獲取recipient和message列，但您CREATE查詢只增加了一個title和body列。這是行不通的。

更改您的代碼有：

private static final String DATABASE_CREATE = 
    "create table notes (" + KEY_ROWID + " integer primary key autoincrement, " 
    + KEY_RECIPIENT + " text not null, " + KEY_MESSAGE + " text not null);"; 

Answer 2

隨着紀堯姆描述的問題，也是你的列名在創建查詢是「體」，並在獲取票據時，使用的是「消息」作爲列名...因此，如果我沒有錯誤地得到這些東西，它可能會導致問題。

編輯：

我希望，它沒有錯什麼，我認爲，你想從表「備註」作爲信息獲取的身體。如果是這樣，那麼你是什麼編碼是：

... 
public static final String KEY_MESSAGE = "message"; 

... 
private static final String DATABASE_CREATE = 
     "create table notes (_id integer primary key autoincrement, " 
     + "title text not null, body text not null);"; 
... 
public Cursor fetchAllNotes() { 

     return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_RECIPIENT, 
       KEY_MESSAGE}, null, null, null, null, null); 
} 

在這裏，你定義KEY_MESSAGE爲「消息」，當您創建表，你有名字「消息」中沒有列。但你想取它在你的選擇查詢中。

因此，您需要將KEY_MESSAGE設置爲「body」，否則您將不得不在表格中添加名爲「message」的列。