我正在創建一個數據庫,引用另一個數據庫中的鍵的過程。從本質上講,我有一個數據導入,我想保持與將會更改的數據分開,但如果可能,我想通過FOREIGN KEY
引用其他密鑰。據我所知,我需要首先附加數據庫才能實現這一點。這裏是德相關的代碼至今:Android與SQLiteOpenHelper ATTACH sqlite數據庫
public class LogDatabaseHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "log.db";
private static final int DATABASE_VERSION = 1;
private String namesDb;
public LogDatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
namesDb=getNamesDbPath();
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("ATTACH DATABASE ? AS names",new String[]{namesDb});
StringBuilder query=new StringBuilder();
query.append("CREATE TABLE log (");
}
}
然而,這似乎並沒有工作,因爲我得到了以下錯誤:
11-21 17:35:58.176: E/SQLiteLog(9984): (1) statement aborts at 5: [ATTACH DATABASE ? AS names] cannot ATTACH database within transaction
11-21 17:35:58.176: D/AndroidRuntime(9984): Shutting down VM
11-21 17:35:58.176: W/dalvikvm(9984): threadid=1: thread exiting with uncaught exception (group=0x41a21700)
11-21 17:35:58.191: E/AndroidRuntime(9984): FATAL EXCEPTION: main
11-21 17:35:58.191: E/AndroidRuntime(9984): android.database.sqlite.SQLiteException: cannot ATTACH database within transaction (code 1)
11-21 17:35:58.191: E/AndroidRuntime(9984): at android.database.sqlite.SQLiteConnection.nativeExecuteForChangedRowCount(Native Method)
11-21 17:35:58.191: E/AndroidRuntime(9984): at android.database.sqlite.SQLiteConnection.executeForChangedRowCount(SQLiteConnection.java:734)
11-21 17:35:58.191: E/AndroidRuntime(9984): at android.database.sqlite.SQLiteSession.executeForChangedRowCount(SQLiteSession.java:754)
11-21 17:35:58.191: E/AndroidRuntime(9984): at android.database.sqlite.SQLiteStatement.executeUpdateDelete(SQLiteStatement.java:64)
11-21 17:35:58.191: E/AndroidRuntime(9984): at android.database.sqlite.SQLiteDatabase.executeSql(SQLiteDatabase.java:1674)
11-21 17:35:58.191: E/AndroidRuntime(9984): at android.database.sqlite.SQLiteDatabase.execSQL(SQLiteDatabase.java:1603)
11-21 17:35:58.191: E/AndroidRuntime(9984): at com.kd7uiy.hamfinder.LogDatabaseHelper.onCreate(LogDatabaseHelper.java:27)
11-21 17:35:58.191: E/AndroidRuntime(9984): at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:252)
11-21 17:35:58.191: E/AndroidRuntime(9984): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
我怎樣才能使這項工作?
您可能需要跳過'SQLiteOpenHelper'或分叉它。在後一種情況下,要麼刪除包裝'onCreate()'的標準事務(自己處理它),要麼讓自己有機會在任何事務邊界之外運行'ATTACH'。 – CommonsWare