Dropping a Datafile and Deleting its References

Question

Using sqlplus how do I delete datafiles and any references to them?
At the moment I start the database in mount mode and use:
ALTER DATABASE DATAFILE 'O:\BCS\test.ora' OFFLINE DROP;
Which drops the datafile, but when I try to open the database it fails because it is still referencing the datafile.
How do I delete this reference?
Any thoughts or suggestions are greatly appreciated.
Regards
Toby

Answer 1

I usually use the following sql to see what is in a tablespace before I drop it with
"drop tablespace users including contents and datafiles;"
column meg format 999999999
column tablespace_name format a20
set wrap off
set lines 120
set heading on
set pages 50
select round(sum(a.bytes)/1024/1024) meg,
count(*) extents,a.tablespace_name,a.segment_type,a.owner||'.'||a.segment_name
from dba_extents a
where a.tablespace_name=upper('&1')
group by a.tablespace_name,a.segment_type,a.owner||'.'||a.segment_name
order by round(sum(a.bytes)/1024/1024)
I also map the contents of datafiles with the following you can get the file_id from v$datafile or dba_data_files:
column owner format a30
column object format a30
set lines 120
set wrap off
set trunc off
set pages 50
set feedback on
column file_id format 999
select     /*+ Rule */     'free space' owner     /*"owner" of free space*/
,          ' ' object          /*blank object name*/
,          file_id                    /*file id for the extent header*/
,          block_id               /*block id for the extent header*/
,          blocks                    /*length of the extent, in blocks*/
from          dba_free_space
where          file_id=&1
union
select     /*+ Rule */ substr(owner,1,20)||' '||substr(segment_type,1,9) /*owner name (first 20 chars)*/
,          substr(segment_name,1,32)||'.'||partition_name     /*segment name*/
,          file_id                    /*file id for the extent header*/
,          block_id               /*block id for the extent header*/
,          blocks                    /*length of the extent, in blocks*/
from           dba_extents
where          file_id=&1
order by     3,4
And datafiles can be dropped in 10g if they are empty:
alter tablespace users drop datafile '/oracle/oradata/users01.dbf';
Good luck