onUpgrade()未被调用-安卓
onUpgrade()未被调用-安卓
提问于 2013-01-05 03:39:08
我在我的表中添加了一个列(SUM)。我以为要重写/重新创建表，只需递增DATABASE_VERSION的变量，但这并不起作用。我的onUpgrade()方法中是否需要一些东西？
版本变量：
private static final int DATABASE_VERSION = 3; 构造函数：
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, DATABASE_VERSION);
}onUpgrade()和onCreate()方法：
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE + " ("
+ RANK + " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ SCORE + " LONG,"
+ PERCENTAGE + " INTEGER,"
+ SUM + " LONG"
+ ");");
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}LogCat输出
01-04 02:00:24.635: E/AndroidRuntime(6224): FATAL EXCEPTION: main
01-04 02:00:24.635: E/AndroidRuntime(6224): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.test/com.example.test.Results}: android.database.sqlite.SQLiteException: no such column: sum (code 1): , while compiling: SELECT sum FROM HighscoresList
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.app.ActivityThread.access$600(ActivityThread.java:141)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.os.Handler.dispatchMessage(Handler.java:99)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.os.Looper.loop(Looper.java:137)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.app.ActivityThread.main(ActivityThread.java:5039)
01-04 02:00:24.635: E/AndroidRuntime(6224): at java.lang.reflect.Method.invokeNative(Native Method)
01-04 02:00:24.635: E/AndroidRuntime(6224): at java.lang.reflect.Method.invoke(Method.java:511)
01-04 02:00:24.635: E/AndroidRuntime(6224): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-04 02:00:24.635: E/AndroidRuntime(6224): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-04 02:00:24.635: E/AndroidRuntime(6224): at dalvik.system.NativeStart.main(Native Method)
01-04 02:00:24.635: E/AndroidRuntime(6224): Caused by: android.database.sqlite.SQLiteException: no such column: sum (code 1): , while compiling: SELECT sum FROM HighscoresList
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:882)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:493)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1314)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1253)
01-04 02:00:24.635: E/AndroidRuntime(6224): at com.example.test.DatabaseHelper.check(DatabaseHelper.java:82)
01-04 02:00:24.635: E/AndroidRuntime(6224): at com.example.test.Results.showResults(Results.java:111)
01-04 02:00:24.635: E/AndroidRuntime(6224): at com.example.test.Results.onCreate(Results.java:60)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.app.Activity.performCreate(Activity.java:5104)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
01-04 02:00:24.635: E/AndroidRuntime(6224): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
01-04 02:00:24.635: E/AndroidRuntime(6224): ... 11 more回答 5
Stack Overflow用户
回答已采纳
发布于 2013-01-05 03:41:40
可以，在onUpgrade中，您需要实际更新表，即添加以下列：
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (oldVersion < 3) {
db.execSQL("ALTER TABLE " + TABLE + " ADD COLUMN " + SUM + " LONG");
}
}如果需要，您可能还希望返回并为每一行填充有效的"sum“值。
Stack Overflow用户
发布于 2013-01-05 03:41:11
您的onUpgrade()方法为空：
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}在最基本的级别上，您需要添加代码来删除现有表并调用onCreate()，然后再次递增DATABASE_VERSION。
private static final int DATABASE_VERSION = 4;
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.exec("DROP TABLE IF EXISTS " + TABLE);
onCreate(db);
}Stack Overflow用户
发布于 2013-01-05 03:42:35
您需要在onUpgrade中重新创建表
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}
db.execSQL("DROP TABLE IF EXISTS " + TABLE);
onCreate(db);
}或者添加以下列：
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}
db.execSQL("ALTER TABLE " + TABLE + " ADD COLUMN `SUM` LONG");
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/14163759
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