我正在迁移我的旧Android项目达到新标准，我陷入了困境room database，无法找到如何执行这2个SQLite命令使用room database。我有两个查询以嵌套方式工作，因此要使用以下命令获得相同的结果room有没有可能。
default public ArrayList getOfflineRoomsAndObjectsByParentIds(String parentId, String site_id, Context context) {
databaseHandler = new DatabaseHandler(context);
Cursor cr = null;
ArrayList<Room> offlineRoomNamesList = new ArrayList<>();
try {
**sqLiteDatabase = databaseHandler.getReadableDatabase();
String query = "SELECT * FROM " + Constants.TABLE_ROOM_NAMES
+ " WHERE " + Constants.SITE_ID + " = '" + site_id + "' AND " + Constants.PARENT_ID + "='" + parentId + "'";**
cr = sqLiteDatabase.rawQuery(query, null);
if (cr.moveToFirst()) {
do {
Room room = new Room();
**room.setId(cr.getString(cr.getColumnIndex(Constants.KEY_ROOM_ID)));
query = "SELECT * FROM " + Constants.TABLE_OFFLINE_ROOM_OBJECTS
+ " WHERE " + Constants.KEY_ROOM_KEY + " = ?"
+ " AND " + Constants.SITE_ID + " = ? ORDER BY " + Constants.KEY_OBJECT_NAME;**
Cursor cursor = sqLiteDatabase.rawQuery(query, new String[]{cr.getString(cr.getColumnIndex(Constants.KEY_ROOM_KEY)), site_id});
if (cursor.moveToFirst()) {
do {
RoomObject roomObject = new RoomObject();
roomObject.setRoomKey(cursor.getString(cursor.getColumnIndex(Constants.KEY_ROOM_KEY)));
roomObject.setId(cursor.getInt(cursor.getColumnIndex(Constants.KEY_ID)));
roomObject.setInstanceNumber(cursor.getInt(cursor.getColumnIndex(Constants.KEY_INSTANCE_NUMBER)));
roomObject.setObjectType(cursor.getString(cursor.getColumnIndex(Constants.KEY_OBJECT_TYPE)));
String mergeKey = AppSharedPreference.getString(AppSharedPreference.MERGE_KEY, "", context);
if (roomObject.getObjectName().contains(mergeKey) && !TextUtils.isEmpty(mergeKey)) {
room.addMergeableObjectsInList(roomObject);
} else {
room.addRoomObjectsInList(roomObject);
}
}
while (cursor.moveToNext());
}
if (room.getRoomObjectsList().size() > 0)
offlineRoomNamesList.add(room);
cursor.close();
} while (cr.moveToNext());
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
cr.close();
sqLiteDatabase.close();
} catch (Exception e) {
e.printStackTrace();
}
}
return offlineRoomNamesList;
}
我现在看到的唯一可能性是两个定义两个不同的查询并以嵌套方式执行它们。
@Dao
public interface ControllerRoomObjectDao {
@Query("SELECT * FROM room_names WHERE site_id=:siteId AND parentId=:parentId")
Single<List<Room>>getOfflineRoomsAndObjectsByParentId(String siteId, String parentId);
@Query("SELECT * FROM offline_objects WHERE site_id=:siteId AND parentId=:parentId")
Single<List<RoomObject>>getOfflineObjectsByParentId(String siteId, String parentId);
}
您可以将databaseView用于您的用例
例如：
@DatabaseView("SELECT user.id, user.name, user.departmentId," +
"department.name AS departmentName FROM user " +
"INNER JOIN department ON user.departmentId = department.id")
public class UserDetail {
public long id;
public String name;
public long departmentId;
public String departmentName;
}
了解更多信息https://developer.android.com/training/data-storage/room/creating-views#java https://developer.android.com/training/data-storage/room/creating-views#java
本文内容由网友自发贡献，版权归原作者所有，本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容，请联系:hwhale#tublm.com(使用前将#替换为@)
