Dropping Unused column
Hi All,
I am working on version 11.2.0.3.0 ( windows server 2008 ).
While dropping unused column i am getting below error
SQL> create table er (ab varchar2(50), aa varchar2(50)) compress;
SQL> alter table er set unused column ab;
Table altered.
SQL>
SQL>
SQL>
SQL>
SQL> alter table er drop unused columns;
alter table er drop unused columns
ERROR at line 1:
ORA-39726: unsupported add/drop column operation on compressed tables
i can't do such things for these number of tablesThat is the funniest thing I've heard in a while. If you can "alter table xxx drop unused columns," why can't you do what is suggested.
And no, it's not a bug.
And no, there is not "another way around"
Similar Messages
-
Drop unused column in compressed table
Good day for all.
I have partitioned compressed table under 10.2.0.4 database. I need to remove column, and did it according metalink note 429898.1, but then i execute command alter table .... drop unused columns, i got error ORA-39726 (unsupported add/drop column operation for compreseed table), so it mean that proposed workaround don't works now.
Does anyone have new workaround for this problem?alter table MY_TABLE set unused(MY_FNG_COLUMN);
-- success
alter table MY_TABLE drop unused columns;
-- error -
Dear Gurus
I have a situation where I need to drop specific columns which are set to unused!
Say, I have 3 unused columns in a table and now I want to drop only one unused column from that.
SQL> alter table scott.emptest set unused (ENAME);
Table altered.
SQL> alter table scott.emptest set unused (COMM);
Table altered.
Once I set some columns un-used, now I want to drop only one un-used Column ENAME
SQL> alter table scott.emptest drop column ENAME;
alter table scott.emptest drop column ENAME
ERROR at line 1:
ORA-00904: "ENAME": invalid identifier
which in turn throws this error!
Help appreciated!
Thanks in advanced
Ravi PrakashSCOTT@demo102> create table tbl_25 as select * from emp
SCOTT@demo102> /
Table created.
SCOTT@demo102> desc tbl_25
Name Null? Type
EMPNO NUMBER(4)
ENAME VARCHAR2(10)
JOB VARCHAR2(9)
MGR NUMBER(4)
HIREDATE DATE
SAL NUMBER(7,2)
COMM NUMBER(7,2)
DEPTNO NUMBER(2)
SCOTT@demo102> alter table tbl_25 set unused (deptno)
SCOTT@demo102> /
Table altered.
SCOTT@demo102> alter table tbl_25 set unused (comm);
Table altered.
SCOTT@demo102> desc tbl_25
Name Null? Type
EMPNO NUMBER(4)
ENAME VARCHAR2(10)
JOB VARCHAR2(9)
MGR NUMBER(4)
HIREDATE DATE
SAL NUMBER(7,2)
SCOTT@demo102> select * from all_unused_col_tabs where table_name ='TBL_25';
OWNER TABLE_NAME COUNT
SCOTT TBL_25 2
SCOTT@demo102> alter table tbl_25 drop unused column;
Table altered.
SCOTT@demo102> select * from all_unused_col_tabs where table_name ='TBL_25';
no rows selected
SCOTT@demo102> Nicolas.
Add queries on all_unused_col_tabs.
Message was edited by:
N. Gasparotto -
Dropping unused columns from database table
I have an existing table called TUSER. I have mapped some fields, but not
all fields, as some are inserted by other applications and for reporting
purposes.
I am using JDK 1.3.1_02, Windows 2000, SQL Server 2000 database, Kodo
JDOEE 2.2.6 and JBoss 3.0.0.
When I refresh the datastore it drops all columns that are not mapped
(note that these colums can contain null values):
[java] [ connection: 2961925; statement: 2766626; time: Thu Jul 04
15:33:22 JST 2002 ] ALTER TABLE TUSER ADD Job_Title_ID VARCHAR(255)
[java] [ connection: 2961925; statement: 1582473; time: Thu Jul 04
15:33:22 JST 2002 ] ALTER TABLE TUSER DROP COLUMN MAILUSERID
[java] [ connection: 2961925; statement: 5237832; time: Thu Jul 04
15:33:22 JST 2002 ] ALTER TABLE TUSER DROP COLUMN PHONENUMBERS
[java] [ connection: 2961925; statement: 2191491; time: Thu Jul 04
15:33:22 JST 2002 ] ALTER TABLE TUSER DROP COLUMN EMPLOYEENO
[java] [ connection: 2961925; statement: 894443; time: Thu Jul 04
15:33:22 JST 2002 ] ALTER TABLE TUSER DROP COLUMN MDATE
[java] [ connection: 2961925; statement: 531758; time: Thu Jul 04
15:33:22 JST 2002 ] ALTER TABLE TUSER DROP COLUMN STATUSCHANGETIME
[java] [ connection: 2961925; statement: 5899013; time: Thu Jul 04
15:33:23 JST 2002 ] ALTER TABLE TUSER DROP COLUMN FINISHDATE
[java] [ connection: 2961925; statement: 8146001; time: Thu Jul 04
15:33:23 JST 2002 ] ALTER TABLE TUSER DROP COLUMN LASTLOGGEDMBOARD
[java] [ connection: 2961925; statement: 7756310; time: Thu Jul 04
15:33:23 JST 2002 ] ALTER TABLE TUSER DROP COLUMN DEL_FLG
[java] [ connection: 2961925; statement: 6817858; time: Thu Jul 04
15:33:23 JST 2002 ] ALTER TABLE TUSER DROP COLUMN PERMIT_CD
[java] [ connection: 2961925; statement: 7754670; time: Thu Jul 04
15:33:23 JST 2002 ] ALTER TABLE TUSER DROP COLUMN LASTLOGGEDREQUESTER
[java] [ connection: 2961925; statement: 7332084; time: Thu Jul 04
15:33:24 JST 2002 ] ALTER TABLE TUSER DROP COLUMN MSG_SERVER
[java] [ connection: 2961925; statement: 1691809; time: Thu Jul 04
15:33:24 JST 2002 ] ALTER TABLE TUSER DROP COLUMN AUTORUN
[java] [ connection: 2961925; statement: 5253969; time: Thu Jul 04
15:33:24 JST 2002 ] ALTER TABLE TUSER DROP COLUMN REG_DATE
[java] [ connection: 2961925; statement: 4977422; time: Thu Jul 04
15:33:24 JST 2002 ] ALTER TABLE TUSER DROP COLUMN PERMIT_LST
[java] [ connection: 2961925; statement: 4343712; time: Thu Jul 04
15:33:24 JST 2002 ] ALTER TABLE TUSER DROP COLUMN ALLOWREPL
[java] [ connection: 2961925; statement: 7104150; time: Thu Jul 04
15:33:24 JST 2002 ] ALTER TABLE TUSER DROP COLUMN EMAIL
[java] [ connection: 2961925; statement: 4395840; time: Thu Jul 04
15:33:24 JST 2002 ] ALTER TABLE TUSER DROP COLUMN MANAGERSTATUS
[java] [ connection: 2961925; statement: 2417379; time: Thu Jul 04
15:33:24 JST 2002 ] ALTER TABLE TUSER DROP COLUMN MD5_DIGEST
[java] [ connection: 2961925; statement: 2865120; time: Thu Jul 04
15:33:25 JST 2002 ] ALTER TABLE TUSER DROP COLUMN SMTPADDRESS
15:33:25 JST 2002 ] INSERT INTO JDO_SCHEMA_METADATAX(CLASSNAMEX) VALUES
('com.gulfnet.g
roupcast.data.User')
Is this meant to happen? I am guessing not. Is there a way to tell the
schematool to not remove existing columns?
Thanks in advance.
KamYou can in fact tell the schematool not to drop columns it doesn't know about. When you run the schematool, use the "add" action rather than "refresh". Then it will only add columns, never drop them. See the documentation for details:
http://www.solarmetric.com/Software/Documentation/2.2.5/manual.html#schema_manipulation -
Hi,
I am having a problem with dropping a column from a table. I am using 10g (10.2.0.1.0). Whenever I try to drop a column I got this error:
ORA-39726: unsupported add/drop column operation on compressed tables
Then I tried to drop it in a way that first make it unused and then drop it but this time I got the following erro: while unused operation was successful
ORA-12996: cannot drop system-generated virtual column
Well I restored this database from RMAN backups of my production system. One thing more that is, when I created a new table then from that table I can drop or add any column from/to it.
Any help........
Arshad.Well I have already tried this. As I explained in my first email that unused worked fine but as soon as I try to drop the unused column I got this error:
ORA-12996: cannot drop system-generated virtual column
Arshad. -
We are planning to drop a column from a production large table with more than 150 million rows.
It is causing an exclusive lock on the table for more than 2 hrs. Is there any way we can reduce the time period for the lock on the table.
We tried setting the column unused and then dropping it but it also causing the lock on the table for hrs.
Is there any way we can drop the column without causing exclusive lock on the same or we can shorten this time.I see you can have two approaches and you can choose which best suites you.
1) DBMS_REDEFINITION
2) Using triggers to capture DML statements along with CTAS.
First approach is an easier approach but is time consuming.
I do not think so you can have downtime for DML operations during dropping of the column.
Regards
Anurag -
How to recover the unused column
According to the spec, 'set unused' does not actually remove the target columns and the column data remains in the table's rows. but if a column was marked as unused, there are no any access to the column. then why the clause is released?is it better than drop column?if the unused columns exist still,why there are no clause to restore it?
http://asktom.oracle.com/pls/ask/f?p=4950:8:::::F4950_P8_DISPLAYID:2913496610745#2914947431112
-
ORA-12983: cannot drop all columns in a table
Hi,
I am creating a table with two columns.
I have modified a column as unused using ALTER statement.
After that i have tried to drop the another column by using ALTER statement.
But it throws an error ORA-12983: cannot drop all columns in a table.
is it not possible to achieve this via ALTER statement?
thanksis there any other way to find the name of the columns which have been marked as unused?Don't think so, and you would not be able to do much about. You won't be able to reference it, you won't be able to un-unuse it, and you would even be able to add a new column having same name.
Why are you using SET UNUSED in the first place?
Regards
Peter
Quoting myself:
You won't be able to reference itMaybe not good enough:
SQL> select column_name, data_type, segment_column_id
from user_tab_cols
where table_name = 'T';
COLUMN_NAME DATA_TYPE SEGMENT_COLUMN_ID
SYS_C00001_11051618:28:14$ NUMBER 1
B NUMBER 2
SYS_C00003_11051618:28:14$ NUMBER 3
3 rows selected.
select "SYS_C00003_11051618:28:14$" from t
Error at line 1
ORA-00904: "SYS_C00003_11051618:28:14$": invalid identifier
SQL> alter table t drop column "SYS_C00001_11051618:28:14$";
Table altered.
SQL> select column_name, data_type, segment_column_id
from user_tab_cols
where table_name = 'T';
COLUMN_NAME DATA_TYPE SEGMENT_COLUMN_ID
B NUMBER
1 row selected.
Note: Both columns "disappeared" Thanks MichaelS
Edited by: Peter on May 16, 2011 9:29 AM -
Hi
I am using around 130 tables in Oracle, now i want to update all the table and want to drop fields from the table which are not used and having blank record.
going to each table and giving command everytime and identifiying a blank field is time taking job, is there any shortcut for this ???
sanjayI won't suggest writing a automated script to identify columns not being used and dropping them without even doing a impact-analysis! A better approach would be:
1) Identify columns not being used (say the ones where all rows have null values)
2) Do impact-analysis to short-list the columns that maybe dropped
3) On a table-to-table basis, write scripts to drop the column or mark it as unused, or write create table statements if mutiple columns of the same table need to be dropped. As suggested by Eric above.
Now for step (1), if all the tables of your schema are analyzed, you may use the following script to identify columns that has null value for all the rows:
select *
from user_tab_columns
where num_distinct = 0
and low_value is null
and high_value is null
and num_nulls > 0 -- this is to ignore tables with no rows!
and avg_col_len = 0
order by table_name, column_id
NOTE: Please be aware that I have not tested the above script on a full live-schema. I have tested it with a test schema having 4 tables, all tables having three number columns (col1, col2 and col3) and a test data of 10,000 rows each:
1. Table 1: col3 having null value for all rows.
2. Table 2: col3 having not-null value for all rows.
3. Table 3: col3 having not-null value in only 1 row.
4. Table 4: Table with no rows. -
Hey guys,
Does any one know how to achieve drag-drop data column
sorting? I tried, but could not find an efficient way to do this.
It would be an awesome spry feature if possible, but if someone
else knows how to do this already it would help.
Thanks,
Timothy D FarrarHey guys,
We aim to be as compatible as possible with the other
frameworks but sometimes problem may exists. We need to see the
crashing pages to be able to determine the causes for the JS error
message and where the incompatibilities are located and either fix
the problems or help you to change your pages to work.
In this situation I suspect the issue appears because the
spry region is generated after the drag and drop code from the
script.aculo.us is instantiated and we destroy the initial elements
to which this widget is binded. In this situation the solution is
to instantiate the drag and drop after the region generate its
content by using the region observers. You'll have to put the drag
and into a separated function and register the code so the region
will call it automatically onPostUpdate.
We include in our documentation more details about the
Region
observer notifications. Please search the dedicated chapter
inside this doc: "Region observer notifications"
Regards,
Cristian MARIN -
Dropping a column in composite xmltype table with virtual column
Hello,
i found some interesting behavior. I have a table with xmltype column and a virtual column. If i drop a column, which has an index smaller than the index for the xmltype column, than the virtual column reference for xmltype column is not changed.
select * from v$version;
drop table t_xml purge;
create table t_xml( c1 number,
c2 number,
cxml xmltype,
c3 number,
xmlflag number as (nvl2(cxml,1,0)));
select * from t_xml;
alter table t_xml drop column c2;
select * from t_xml; The 2nd select will result in error:
SQL> select * from v$version;
BANNER
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
PL/SQL Release 11.2.0.1.0 - Production
CORE 11.2.0.1.0 Production
TNS for IBM/AIX RISC System/6000: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production
SQL> alter table t_xml drop column c2;
Tabelle wurde geändert.
SQL>
SQL> select * from t_xml;
select * from t_xml
FEHLER in Zeile 1:
ORA-00904: "SYS_NC00004$": ungültiger BezeichnerNow the virtual column xmlflag references still the old hidden column for cxml (SYS_NC00004$). It not references the new hidden column, which is now SYS_NC00003$.
I think, it is a bug! Can someone inform oracle? I have no access to metalink.Hi,
Please try this code:
loop at int_inv into wa_inv.
lv_count = lv_count + 1.
AT END OF posnr. <------- The field you want to sum..
gs_total-posnr = wa_inv-posnr.
gs_total-cov_total = lv_count.
APPEND gs_total TO gt_total.
CLEAR : gs_total,
lv_count,
wa_inv.
ENDAT.
ENDLOOP. -
Sir
i am new to database.I am doing an oracle course on 051.My oracle faculty is saying
Set unused column option will hide the column for-ever.user can't retrieve it again.
what i believe if a statement is hiding a column there must be some option to regain it.
Is there any option of to make an unused column to reusable again?Hi,
i am new to database.
Is there any option of to make an unused column to reusable again?Since you're new:
Try to find your answers in the Oracle documentation as well, as it explains clearly how 'Oracle things' work, with examples and you can do quick searches on keywords of your interest.
Example: http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/tables.htm#sthref2329
You should bookmark: http://tahiti.oracle.com and start reading the concepts and fundamentals when you've got some spare time.
assuming you're on 10g -
Hi OTNeites,
How does one drop a column in Oracle 7.2 or Oracle 8.0
Thanks in advance.Something like this.
create new_table as select col1, col2, col3
from old_table
drop old_table
rename new_table to old table
The trick is to select all the columns except the one you want to drop when creating the new table.
In this case you lost all indexes, constraints ...
You should create script for recriate all objects in DB
that will be drop with DROP OLD_TABLE command. -
How to drop unused schema
give ur suggestion
ThanksRobert Geier wrote:
If you are sure it is unused, export the schema to disk (using exp, expdp), then drop it.
drop user xxx cascade;
If you are not sure, then you may want to audit to confirm it is not used, and maybe lock the schema for a month before you drop it.Of course locking the schema (actually, locking the user account that owns the schema) doesn't prevent the objects in the schema from being used, it just prevents the owner of the schema from connecting. In a lot (should I say "most"?) systems, the application schemas are owned by "users" that are already locked, because there is never any intent for that user account to actually connect. So trying to determine if a schema is used by locking the owning account and seeing who screams is not going prove much of anything. -
Dropping a column's default value
How to drop a column's default value?
The following commands fails:
ALTER TABLE t1 ALTER COLUMN c1 DROP DEFAULT.
ALTER TABLE t1 MODIFY c1 DROP DEFAULT.
Thanks in advance.SQL> ALTER TABLE IDENTIFICADORES_DOMINIOS_RANGO MODIFY TIPO_DATO DEFAULT NULL;
Table altered
SQL> DESC IDENTIFICADORES_DOMINIOS_RANGO
Name Type Nullable Default Comments
CODIGO_IDENTIFICADOR NUMBER(7)
DESCRIPCION VARCHAR2(50)
TIPO VARCHAR2(1)
TIPO_DATO VARCHAR2(1) NULL Tipo de dato que contiene el Dominio-RangoI would like drop DEFAULT value; now, it's marked like NULL. It's not the same... is it?
Maybe you are looking for
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