我在我的SQLite数据库中做了ALTER TABLE,现在更新我的应用程序一切都很顺利,但是如果您在未安装旧版本数据库的情况下启动新的APK不会创建新列!为什么? 这是我使用的代码:alter table column does not create
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (newVersion >=2) {
db.execSQL("ALTER TABLE Giornate ADD COLUMN note TEXT");
}
}
在我的辅助类
有在“GIORNATE”几个表我要补充的“注意”栏
@Override
public void onCreate(SQLiteDatabase db) {
BilancioHelper.db = db;
//tabella giornate
StringBuilder builder = new StringBuilder();
builder.append("CREATE TABLE {0} (");
builder.append("{1} INTEGER PRIMARY KEY AUTOINCREMENT,");
builder.append("{2} TEXT,");
builder.append("{3} REAL DEFAULT 0,");
builder.append("{4} REAL DEFAULT 0,");
builder.append("{5} REAL DEFAULT 0,");
builder.append("{6} INTEGER,"); // E' boolean
builder.append("{7} INTEGER"); // E' boolean
builder.append(");");
db.execSQL(MessageFormat.format(builder.toString(),
GiornateTable.TABLE_NAME, GiornateTable._ID,
GiornateTable.DATA, GiornateTable.ENTRATA,
GiornateTable.USCITA, GiornateTable.BANCA, GiornateTable.RIPOSO, GiornateTable.SPESA));
串
public interface GiornateTable extends BaseColumns {
public static final String TABLE_NAME = "Giornate";
public static final String ENTRATA = "entrata";
public static final String DATA = "data";
public static final String USCITA = "uscita";
public static final String BANCA = "banca";
public static final String RIPOSO = "riposo";
public static final String SPESA = "spesa";
public static final String NOTE = "note";
public static final String[] COLUMNS = {_ID, ENTRATA, DATA, USCITA, BANCA, RIPOSO, NOTE};
}
然后,我做这些测试。启动版本1和2然后一切顺利。但如果我投出了唯一的2,那就是崩溃。 logcat的:
08-18 16:54:15.126: E/AndroidRuntime(1258): java.lang.RuntimeException: Unable to start activity ComponentInfo{bilancio.personale/it.della90.bilancio.MainActivity}: java.lang.NullPointerException
08-18 16:54:15.126:E/AndroidRuntime(1258):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 08-18 16:54:15.126 :E/AndroidRuntime(1258):at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 08-18 16:54:15.126:E/AndroidRuntime(1258):at android.app.ActivityThread.access $ 600 ActivityThread.java:141) 08-18 16:54:15.126:E/AndroidRuntime(1258):at android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1234) 08-18 16:54:15.126: E/AndroidRuntime(1258):at android.os.Handler.dispatchMessage(Handler.java:99) 08-18 16:54:15 .126:E/AndroidRuntime(1258):at android.os.Looper.loop(Looper.java:137) 08-18 16:54:15.126:E/AndroidRuntime(1258):at android.app.ActivityThread.main (ActivityThread.java:5041) 08-18 16:54:15.126:E/AndroidRuntime(1258):at java.lang.reflect.Method.invokeNative(Native Method) 08-18 16:54:15.126:E/AndroidRuntime(1258):在java.lang.reflect.Method.invoke(Method.java:511) 08-18 16:54:15.126:E/AndroidRuntime(1258):at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:793) 08-18 16:54:15.126:E/AndroidRuntime(1258):at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 08-18 16:54:15.126:E/AndroidRuntime(1258):在dalvik.system.NativeStart.main(本地方法) 08-18 16:54:15.126:E/AndroidRuntime(1258):引起:java.lang.Nu llPointerException 08-18 16:54:15.126:E/AndroidRuntime(1258):at it.della90.bilancio.db.BilancioHelper.onCreate(BilancioHelper.java:38) 08-18 16:54:15.126:E/AndroidRuntime (1258):at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:252) 08-18 16:54:15.126:E/AndroidRuntime(1258):at android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper .java:188) 08-18 16:54:15.126:E/AndroidRuntime(1258):at it.della90.bilancio.MainActivity.calcolaTotaleRisparmioMese(MainActivity.java:342) 08-18 16:54:15.126:E/AndroidRuntime(1258):at it.della90.bilancio.MainActivity.onCreate(MainActivity.java:112) 08-18 16:54:15.126:E/AndroidRuntime(1258):at android.app.Activity.performCreate(Activity .java:5104) 08-18 16:54:15.126:E/AndroidRuntime(1258):at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 08-18 16:54:15.126:E/AndroidRuntime(1258):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java :2144) 08-18 16:54:15.126:E/AndroidRuntime(1258):... 11更多
是您的表GIORNATE已经创造出来的?如果它不是它不会改变它! ALTER TABLE命令需要一个现有的表,因此它可以应用于它! http://sqlite.org/lang_altertable.html – Pavlos
表已经存在,我只需添加一列,但正如我在我的第一篇文章中所说,如果用户从旧版本更改为新的一切都工作正确地说,如果只安装了新版本的列没有创建?除了改变表格之外,我还应该做些什么? –
如果用户安装新版本,则数据库不存在升级,因为数据库不存在!所以你必须以另一种方式执行表的ALTERnation,而不是在onUpgrade中! – Pavlos