insert（）语句未正确填充SQLite数据库

时间：2012-06-14 20:14:52

标签： android sqlite

最近，我asked a question关于我创建的扩展SQLiteOpenHelper的类，其中insert()语句在Logcat中导致错误。最近，我决定使用ddms来拉取我的应用程序应该充当接口的数据库，然后在终端中查看它。这就是结果：

Pictured: Me viewing a recently pulled version of my app's database 令我惊讶的是，我只看到一个插入语句（无论如何，来自我的应用程序）。我已经在我的应用程序中尝试了多个插入，并且只尝试了最初的＆＃34; Hello world！＆＃34;让它进入。

我不确定问题是什么。任何人都可以帮我弄清楚为什么我的数据库只是自重？我的猜测涉及主键没有正确递增，但我不知道为什么会这样。此外，Logcat中不再出现任何错误。

我已经包括了我班级的建设者，以防他们可能会有所帮助。此外，我还包括自上一个问题以来我对getNewTaskId（）所做的更改：

public NagTasksDatabaseHelper(Context context, String name,
        CursorFactory factory, int version) {
    super(context, name, factory, version);
    // TODO Auto-generated constructor stub
}

/*
public NagTasksDatabaseHelper(Context context, String name,
        CursorFactory factory, int version,
        DatabaseErrorHandler errorHandler) {
    super(context, name, factory, version, errorHandler);
    // TODO Auto-generated constructor stub
    // NOTE TO SELF: Do not use this constructor. DatabaseErrorHandler only exists in Honeycomb onward.
}
*/
public NagTasksDatabaseHelper(Context context, CursorFactory factory){
    super(context, "NagTasks", factory, 1);
}
public NagTasksDatabaseHelper(Context context) //Most frequently use constructor
{
    super(context, "NagTasks", null, 1);
}
public int getNewTaskId(SQLiteDatabase db)
{
    Cursor c = db.rawQuery("SELECT MAX(_id) FROM TASKS", null);
    c.moveToFirst();
    int columnID = c.getColumnIndex(ID);
    if (columnID == -1)
    {
        c.close();
        return 0;
    } else {
        int newTaskID = c.getInt(columnID) +1;
        c.close();
        return newTaskID;
    }
}
public void addTask(String title, String notes)
{
    SQLiteDatabase db = getWritableDatabase();
    int newestID = getNewTaskId(db);
    ContentValues values = new ContentValues();
    values.put("_id", newestID);
    values.put("TASK", title);
    values.put("NOTE", notes);
    values.put("ISCHECKED", 0);
    db.insert("TASKS", null, values);
    db.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE IF NOT EXISTS TASKS (_id INTEGER PRIMARY KEY, TASK TEXT, NOTE TEXT, ISCHECKED INTEGER);");
}

编辑：我将getColumnIndex()行更改为getColumnIndexorThrow()并在LogCat中收到了这些错误：

06-17 18:47:40.557: V/LoaderManager(329): onLoadComplete: LoaderInfo{44f2ac00 #854 : SQLiteCursorLoader{44f2b950}}
06-17 18:47:40.557: V/LoaderManager(329):   onLoadFinished in SQLiteCursorLoader{44f2b950 id=854}: SQLiteCursor{44ee0800}
06-17 18:47:51.887: D/AndroidRuntime(329): Shutting down VM
06-17 18:47:51.887: W/dalvikvm(329): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
06-17 18:47:51.907: E/AndroidRuntime(329): FATAL EXCEPTION: main
06-17 18:47:51.907: E/AndroidRuntime(329): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mowdownDevelopments.nagTasks/com.mowdownDevelopments.nagTasks.NagTasksAddTasksActivity}: java.lang.IllegalArgumentException: column '_id' does not exist
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.os.Handler.dispatchMessage(Handler.java:99)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.os.Looper.loop(Looper.java:123)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.app.ActivityThread.main(ActivityThread.java:4627)
06-17 18:47:51.907: E/AndroidRuntime(329):  at java.lang.reflect.Method.invokeNative(Native Method)
06-17 18:47:51.907: E/AndroidRuntime(329):  at java.lang.reflect.Method.invoke(Method.java:521)
06-17 18:47:51.907: E/AndroidRuntime(329):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
06-17 18:47:51.907: E/AndroidRuntime(329):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
06-17 18:47:51.907: E/AndroidRuntime(329):  at dalvik.system.NativeStart.main(Native Method)
06-17 18:47:51.907: E/AndroidRuntime(329): Caused by: java.lang.IllegalArgumentException: column '_id' does not exist
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.database.AbstractCursor.getColumnIndexOrThrow(AbstractCursor.java:314)
06-17 18:47:51.907: E/AndroidRuntime(329):  at com.mowdownDevelopments.nagTasks.NagTasksDatabaseHelper.getNewTaskId(NagTasksDatabaseHelper.java:127)
06-17 18:47:51.907: E/AndroidRuntime(329):  at com.mowdownDevelopments.nagTasks.NagTasksDatabaseHelper.getNewTaskId(NagTasksDatabaseHelper.java:141)
06-17 18:47:51.907: E/AndroidRuntime(329):  at com.mowdownDevelopments.nagTasks.NagTasksAddTaskFragment.onActivityCreated(NagTasksAddTaskFragment.java:42)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:891)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1080)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1062)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:1810)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:501)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1129)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.app.Activity.performStart(Activity.java:3781)
06-17 18:47:51.907: E/AndroidRuntime(329):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2636)
06-17 18:47:51.907: E/AndroidRuntime(329):  ... 11 more
06-17 18:47:58.947: I/Process(329): Sending signal. PID: 329 SIG: 9

...那么，＆＃34; _id＆＃34;不存在？它将解释旧版本总是如何传递0。

3 个答案:

答案 0 :(得分：1)

  

我的猜测涉及主键没有正确递增，但是   我不知道为什么会这样。

因此您的_id不会自动递增，因为您没有指定它的递增。 因此，请将此onCreate方法替换为：

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE TASKS (_id INTEGER PRIMARY KEY AUTOINCREMENT, TASK TEXT, NOTE TEXT, ISCHECKED INTEGER);");
}

您必须为AUTOINCREMENT指定_id。

您没有在插入数据的地方添加代码，但是您应该使用insert()与[{1}}组合的SQLiteDatabase方法。

ContentValues

另外，您应该在public boolean addNewData(String name, String address) { ContentValues data = new ContentValues(); data.put("NameColumn", name); data.put("AddressColumn", address); db.insert("TASKS", "NameColumn", data); } 或close()方法中调用SQLite onStop方法。 只需在这里添加更多代码片段或整个实现。

修改

getNewTask示例

onDestroy

答案 1 :(得分：0)

不应该是

int columnID = c.getColumnIndex("_id"); // not ID

你总是从getNewTaskId

返回0

答案 2 :(得分：0)

因此，事实证明问题实际上是传递给getColumnIndex()的列名实际上是不存在的。因此，简单的解决方法是为MAX(_id) ...

分配别名 
public int getNewTaskId(SQLiteDatabase db)
{
    Cursor c = db.rawQuery("SELECT MAX(_id) AS max FROM TASKS", null);
    c.moveToFirst();
    int columnID = c.getColumnIndex("max");
    if (columnID == -1)
    {
        c.close();
        return 0;
    } else {
        int newTaskID = c.getInt(columnID) +1;
        c.close();
        return newTaskID;
    }
}

这解决了这个问题。

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