The order is:
It is necessary to disconnect tablespace (but not the file as you did)
ALTER TABLESPACE "INDX" OFFLINE;
To mark all indexes in this tablespace as unusable and to reconstruct.
For example:
BEGIN
FOR c_rec IN (SELECT a.index_name
FROM SYS.all_indexes a
WHERE a.owner = 'SUPERMAG' AND a.tablespace_name = 'INDX')
LOOP
BEGIN
EXECUTE IMMEDIATE 'ALTER INDEX ' || t_rec.table_name || ' UNUSABLE';
EXECUTE IMMEDIATE 'ALTER INDEX ' || t_rec.table_name || ' REBUILD TABLESPACE NEW_INDX';
END;
END LOOP;
END;
And then to remove old tablespace.
You can still try to make export and import. While gives the chance - do export.
If nothing helps, you have to restore the file .dbf through DBF Viewer Tool. http://www.dbf.viewertool.com/[/url]
Just in case go to this forum and look at the topic