Single update statement

I have 20 or more update statement like below, I am trying to get this as a single
update statement to make it easier, can someone pls help me?
Update Product
Set sku_id = (Select sku_id From Product_base
                     Where Product_Code ='WWT204')
Where sku_id = (Select sku_id From Product_base
                     Where Product_Code ='9HRC04');
Update Product
Set sku_id = (Select sku_id From Product_base
                     Where Product_Code ='WWT205')
Where sku_id = (Select sku_id From Product_base
                     Where Product_Code ='9HRC05');
Update Product
Set sku_id = (Select sku_id From Product_base
                     Where Product_Code ='WWT206')
Where sku_id = (Select sku_id From Product_base
                     Where Product_Code ='9HRC06');
etc...
etc..

In general, it can't be done since it is possible sku_id updated by first UPDATE will be updated by second or third or... UPDATE. Assuming each UPDATE affects unique set of sku_id:
update product p
set sku_id = (
                select (
                         select sku_id
                           from product_base pb2
                           where product_code = case pb1.product_base
                                                  when '9HRC04' then 'WWT204'
                                                  when '9HRC05' then 'WWT205'
                                                  when '9HRC06' then 'WWT206'
                                                end
                  from product_base pb1
                  where pb1.sku_id = p.sku_id
                    and product_code in ('9HRC04','9HRC05','9HRC06')
where sku_id in (
                    select sku_id
                      from product_base
                      where product_code in ('9HRC04','9HRC05','9HRC06')
                   );SY.

Similar Messages

How to convert pl/sql block into single update statement

Dear all gurus,
I have pl/sql block mention below, Can I convert this pl/sql block to single update statement if possible?
If not how to optimize this block?
Pleaese suggest.
thanks in advance.
Vijay
DECLARE
CURSOR vt_mlr_cursor IS Select master_key, user4 from vt_mlr Where USER4 is not null;
USERFIELD VARCHAR2(100);
C1 VARCHAR2(3); /* this will return location of first space = 12 */
C2 VARCHAR2(3); /* this will return location of second space = 20 */
C3 VARCHAR2(3); /* this will return location of third space = 28 */
C4 VARCHAR2(3); /* this will return location of forth space = 35 */
Field1 VARCHAR2(40); /* this will return FTMYFLXA04W */
Field2 VARCHAR2(10); /* this will return VPI0043 */
Field3 VARCHAR2(10); /* this will return VCI0184 */
Field4 VARCHAR2(10); /* this will return 005 */
Field5 VARCHAR2(10); /* this will return 00001 */
Field_2_n_3 VARCHAR2(25);
key VARCHAR2(10);
BEGIN
FOR vt_mlr_record IN vt_mlr_cursor
LOOP
key := vt_mlr_record.master_key;
USERFIELD := vt_mlr_record.user4;
C1 := INSTR(vt_mlr_record.user4,' ',1,1); /* this will return location of first space = 12 */
C2 := INSTR(vt_mlr_record.user4,' ',1,2); /* this will return location of second space = 20 */
C3 := INSTR(vt_mlr_record.user4,' ',1,3); /* this will return location of third space = 28 */
C4 := INSTR(vt_mlr_record.user4,' ',1,4); /* this will return location of forth space = 35 */
Field1 := SUBSTR(vt_mlr_record.user4,1,C1-1); /* this will return FTMYFLXA04W */
Field2 := SUBSTR(vt_mlr_record.user4,C1+4,C2-C1-4); /* this will return VPI0043 */
Field3 := SUBSTR(vt_mlr_record.user4,C2+4,C3-C2-4); /* this will return VCI0184 */
Field4 := SUBSTR(vt_mlr_record.user4,C3+4,C4-C3-4); /* this will return 005 */
Field5 := SUBSTR(vt_mlr_record.user4,C4+4,LENGTH(vt_mlr_record.user4)-C4-3); /* this will return 00001 */
Field_2_n_3 := Field2 || '/' || Field3;
/*DBMS_OUTPUT.PUT_LINE ('Current key is: ' || vt_mlr_record.master_key);*/
UPDATE vt_mlr
SET
aggregator_clli = Field1,
aggregator_vpi_vci = Field_2_n_3,
aggregator_slot = Field4,
aggregator_port = Field5
WHERE
master_key = vt_mlr_record.master_key;
END LOOP;
END;
/

Hi Vijay,
Here's something to start with, you should be able to complete it.
First, combine your select and update statements:
update vt_mlr
   set aggregator_clli = field1
      ,aggregator_vpi_vci = field_2_n_3
      ,aggregator_slot = field4
      ,aggregator_port = field5
where user4 is not null;Then put these two
C1 := INSTR(vt_mlr_record.user4,' ',1,1);
Field1 := SUBSTR(vt_mlr_record.user4,1,C1-1);into
Field1 := SUBSTR(vt_mlr_record.user4,1,INSTR(vt_mlr_record.user4,' ',1,1) -1);And put it into the update statement, removing reference to record
(I have also removed default values for position and occurrence in instr function):
update vt_mlr
   set aggregator_clli = substr(user4, 1, instr(user4,' ') - 1)
      ,aggregator_vpi_vci = field_2_n_3
      ,aggregator_slot = field4
      ,aggregator_port = field5
where user4 is not null; I think you can do the rest from here ;-)
Regards
Peter

Optimize single update statement

Hi all, I've got a table with about 50 millions of rows (a spatial network...) and I have to issue an update statement without any where condition.
The statement is: UPDATE NODE SET ACTIVE='Y';
Which is the most efficient way to do this?
A single UPDATE statement, the forall loop or an incremental FOR loop with partial commit (each 1000 rows i.e.)?
Thanks
Lorenzo

Or a single MERGE statement.
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:6407993912330#57387981485901
You'd test with a subset before to see what performs fastest, ofcourse...

Update multiple columns with single update statement..

HI all,
i am reading the columns value from different table but i want to update it with signle update statement..
such as how to update multiple columns (50 columns) of table with single update statement .. is there any sql statement available i know it how to do with pl/sql..

As I understood, may be this. Here i am updating ename,sal, comm columns all at once.
SQL> select * from emp where empno=7369;
     EMPNO ENAME      JOB              MGR HIREDATE                   SAL       COMM     DEPTNO
      7369 SMITH      CLERK           7902 17/12/1980 12:00:00        800                    20
SQL> UPDATE emp
2     SET ename = lower (ename),
3         sal = sal + 1000,
4         comm = 100
5   WHERE empno = 7369;
1 row updated.
SQL> select * from emp where empno=7369;
     EMPNO ENAME      JOB              MGR HIREDATE                   SAL       COMM     DEPTNO
      7369 smith      CLERK           7902 17/12/1980 12:00:00       1800        100         20
SQL> UPDATE emp
2     SET ename = (SELECT 'ABCD' FROM DUAL),
3         sal = (SELECT 1000 FROM DUAL),
4         comm = (SELECT 100 FROM DUAL)
5   WHERE empno = 7369;
1 row updated.

Updating multiple fields using a single update statement.

Hi All,
I am a beginner to Oracle. I have used the following Hint in an update query that is executed in Oracle 10G. We recently updated the Oracle to version 11g and when executing the query getting the following Error: ORA-01779: cannot modify a column which maps to a non key-preserved table. PFB the query. Please suggest me some ways that I can do to avoid this error.
UPDATE /*+ bypass_ujvc */
(SELECT t1.STG_DEL_CONDITION, t2.condition
FROM stg_reports_membenft_latest T1 JOIN (select ods_ssn_grp,sys_id, first_value(STG_DEL_CONDITION) over(PARTITION BY ods_ssn_grp,sys_id
ORDER BY STG_DEL_CONDITION DESC) AS
condition from stg_reports_membenft_latest) T2
ON T1.ods_ssn_grp = T2.ods_ssn_grp AND T1.SYS_ID=T2.SYS_ID ) x
SET x.STG_DEL_CONDITION = x.condition;
Thanks and Regards,
Karthik Sivakumar.

I used the below query and got the Result.
Thank You all
MERGE INTO stg_reports_membenft_latest x1
USING (SELECT distinct ods_ssn_grp,
sys_id,
First_value(STG_DEL_CONDITION) OVER(partition BY ods_ssn_grp,sys_id
ORDER BY STG_DEL_CONDITION DESC)
AS condition
FROM stg_reports_membenft_latest) x2
ON ( x1.ods_ssn_grp = x2.ods_ssn_grp
AND x1.SYS_ID = x2.sys_id )
WHEN matched THEN
UPDATE SET x1.STG_DEL_CONDITION=x2.condition;

Is their any limit on the number of column updates in a update statement!

Hello All,
Is their any limit on the number of columns to set in a single update statement.+
am using oracle 11g .
example :-
UPDATE FMLY SET as_comp1 = v_as_comp1 , as_comp2 = v_as_comp2, as_comp3 = v_as_comp3, as_comp4 = v_as_comp4 , as_comp5 = v_as_comp5 , perslt18 = v_perslt18 , persot64 = v_persot64 , fam_size = v_fam_size , numchild = total_children , C_AGE1 = v_c_age1, C_AGE2 = v_c_age2, C_AGE3 = v_c_age3, C_AGE4 = v_c_age4 WHERE FAMID = fmly_famid(i) ;
and also is it good practice to issue single update or multiple updates ?
example for the above update i can have multiple statements like .. does the performance matters if so which is good
UPDATE FMLY SET as_comp1 = v_as_comp1 , as_comp2 = v_as_comp2, as_comp3 = v_as_comp3, as_comp4 = v_as_comp4 , as_comp5 = v_as_comp5
WHERE FAMID = fmly_famid(i) ;
UPDATE FMLY SET perslt18 = v_perslt18 , persot64 = v_persot64 , fam_size = v_fam_size
WHERE FAMID = fmly_famid(i) ;
UPDATE FMLY SET numchild = total_children WHERE FAMID = fmly_famid(i) ;
UPDATE FMLY SET C_AGE1 = v_c_age1, C_AGE2 = v_c_age2, C_AGE3 = v_c_age3, C_AGE4 = v_c_age4 WHERE FAMID = fmly_famid(i) ;
thanks/kumar
Edited by: kumar73 on Sep 25, 2010 8:38 AM

If you can do it in a single SQL statement then you should do that.
Here's a mantra that I found to work out pretty good:
http://asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:73891904732164

Need a help on Update statement

Hi All,
I Need a help in updating a table column. PFB my requirement.
Table1
ItemID OrgId       Date
1       82     12/sep/2012
2       82     25/oct/2012
3       82     17/Nov/2012
4     82     22/Jan/2013
5     82     26/sep/2012
Table2
Itemid     orgid       Date1
1      82     23/sep/2012
2      82     25/Dec/2012
3      82     17/Sep/2012
4      82     22/Feb/2013
5      82     26/Oct/2012
Table3
Itemid     orgid       Date3
1      82     10/sep/2012
7      82     30/Dec/2012
3      82     12/Sep/2012
10      82     27/Feb/2013
5      82     29/Oct/2012
I Need to Update Date column of Table1 With Date3 of table3
If
Item and org combination is present in table3 and date column of table1 is less than Date3 of table3
Else
I need to Update with date2 of table2.Can we acheive this in a single update statement, can any one help me on this.
Thanks and regards,
Rakesh
Edited by: Venkat Rakesh on Sep 27, 2012 11:04 PM

You can probably also use MERGE:
--DROP TABLE table1;
--DROP TABLE table2;
--DROP TABLE table3;
ALTER SESSION SET nls_language = 'AMERICAN';
CREATE TABLE table1
   itemid    CHAR (1),
   orgid     CHAR (2),
   thedate   DATE
INSERT INTO table1   SELECT '1', '82', TO_DATE ('10/sep/2011', 'dd/mon/yyyy') FROM DUAL;
INSERT INTO table1   SELECT '2', '82', TO_DATE ('10/oct/2011', 'dd/mon/yyyy') FROM DUAL;
INSERT INTO table1   SELECT '3', '82', TO_DATE ('10/nov/2011', 'dd/mon/yyyy') FROM DUAL;
INSERT INTO table1   SELECT '4', '82', TO_DATE ('10/jan/2011', 'dd/mon/yyyy') FROM DUAL;
INSERT INTO table1   SELECT '5', '82', TO_DATE ('10/sep/2011', 'dd/mon/yyyy') FROM DUAL;-- won't be updated
CREATE TABLE table2
   itemid    CHAR (1),
   orgid     CHAR (2),
   thedate   DATE
INSERT INTO table2   SELECT '1', '82', TO_DATE ('01/sep/2012', 'dd/mon/yyyy') FROM DUAL;
INSERT INTO table2   SELECT '2', '82', TO_DATE ('01/dec/2012', 'dd/mon/yyyy') FROM DUAL;
INSERT INTO table2   SELECT '3', '82', TO_DATE ('01/sep/2012', 'dd/mon/yyyy') FROM DUAL;
INSERT INTO table2   SELECT '4', '82', TO_DATE ('01/feb/2012', 'dd/mon/yyyy') FROM DUAL;
CREATE TABLE table3
   itemid    CHAR (1),
   orgid     CHAR (2),
   thedate   DATE
INSERT INTO table3   SELECT '2', '82', TO_DATE ('30/dec/2009', 'dd/mon/yyyy') FROM DUAL; -- date less than table1, so picks from table2
INSERT INTO table3   SELECT '4', '82', TO_DATE ('30/mar/2013', 'dd/mon/yyyy') FROM DUAL; -- larger than table1 , so pick this date
-- table1 original data
SELECT * FROM table1;
-- merge new data
MERGE INTO table1
     USING (SELECT NVL (t1.itemid, t2.itemid) itemid,
                   NVL (t1.orgid, t2.orgid) orgid,
                   t2.thedate prefdate ,
                   t1.thedate nextdate
              FROM    table2 t1
                   FULL OUTER JOIN
                      table3 t2
                   ON t1.itemid = t2.itemid AND t1.orgid = t2.orgid) dat
        ON (dat.itemid = table1.itemid AND dat.orgid = table1.orgid)
WHEN MATCHED
THEN
   UPDATE SET table1.thedate = (case when prefdate > table1.thedate then prefdate else nextdate end) ;
--table1 updated data
SELECT * FROM table1;OUTPUT:
Session altered.
Table created.
1 row created.
1 row created.
1 row created.
1 row created.
1 row created.
Table created.
1 row created.
1 row created.
1 row created.
1 row created.
Table created.
1 row created.
1 row created.
ITEMID ORGID THEDATE
1      82    10.09.2011
2      82    10.10.2011
3      82    10.11.2011
4      82    10.01.2011
5      82    10.09.2011
5 rows selected.
4 rows merged.
ITEMID ORGID THEDATE
1      82    01.09.2012
2      82    01.12.2012
3      82    01.09.2012
4      82    30.03.2013
5      82    10.09.2011
5 rows selected.

Help need on update statements

Hi,
How can i write a single update statement instead of these 2 update statements
UPDATE ACCOUNT_TEMP SET REPO_ASSIGN_FLAG = 1
WHERE ARR_ID_ACCT IN
(SELECT LTRIM(ASR1.ARR_ID_ACCT)
FROM ODS_ACCT_STAT_REL ASR1
WHERE ASR1.ACCT_STAT_TYPE = 'SECONDARY'
AND ASR1.ACCT_STAT_CDE IN ('RA','RV'))
UPDATE ACCOUNT_TEMP SET LE_LI_FLAG = 1
WHERE ARR_ID_ACCT IN
(SELECT LTRIM(ASR1.ARR_ID_ACCT)
FROM ODS_ACCT_STAT_REL ASR1
WHERE ASR1.ACCT_STAT_TYPE = 'SECONDARY'
AND ASR1.ACCT_STAT_CDE IN ( 'LI','LV'))
Thanks for your help

update account_temp
set repo_assign_flag = case when
                         arr_id_action in (select ltrim(asr1.apr_id_acct)
                                             from ods_acct_stat_relasr1
                                            where asr1.acct_stat_type = 'SECONDARY'
                                              and asr1.acct_stat_cde in ('RA','RV') then 1
set LE_LI_FLAG       = case when
                         arr_id_acct in (select ltrim(asr1.arr_id_acct)
                                           from ods_acct_stat_rel.asr1
                                          where asr1.acct_stat_type = 'SECONDARY'
                                            and asr1.acct_stat_cde in ('LI', 'LV') THEN 1
;But remember this code will have performace issues dont combine your updated statements if you dont need to.
Code not tested . . .
HTH
Ghulam

How to tune the Update statement for 20 million rows

Hi,
I want to update 20 million rows of a table. I wrote the PL/SQL code like this:
DECLARE
v1
v2
cursor C1 is
select ....
BEGIN
Open C1;
loop
fetch C1 bulk collect into v1,v2 LIMIT 1000
exit when C1%NOTFOUND;
forall i in v1.first..v1.last
update /*+INDEX(tab indx)*/....
end loop;
commit;
close C1;
END;
The above code took 24 mins to update 100k records, so for around 20 million records it will take 4800 mins (80 hrs).
How can I tune the code further ? Will a simple Update statement, instead of PL/SQL make the update faster ?
Will adding few more hints help ?
Thanks for your suggestions.
Regards,
Yogini Joshi

Hello
You have implemented this update in the slowest possible way. Cursor FOR loops should be absolute last resort. If you post the SQL in your cursor there is a very good chance we can re-code it to be a single update statement with a subquery which will be the fastest possible way to run this. Please remember to use the {noformat}{noformat} tags before and after your code so the formatting is preserved.
David

Can I use a select and update statement in a single jsp file?

I want to update the BUY table everytime I would add a SELL transaction.....I want to minus the stocks that I sold to those that Ive bought before.....
note: I used a seperate table in BUY and SELL transaction
After I Have added a transaction, I want to update the buy table. This is my problem, can I used both SELECT and UPDATE statement at the same time in a single jsp file for example like this:
select * from test, test1;
update test
set total_shares=total_shares-Stotal;
where stock_code=Scode AND name_broker=Sbroker;
Can i have both of these statements in the same jsp file in oder to update the buy table?
Or can anyone suggest how can process that update?THANKS!
--------------------

Can i have both of these statements in the same jsp file in oder to update the buy table?Yes. But wouldn't it have been easier just to try it?

Update all null columns value in single row statement

4) Write a single SQL statement to update all the columns of a table to have -9 instead of null value
e.g:
Before update:
C1     C2     C3
null     9     null
10     null     88
12     8     0
After update:
C1     C2     C3
-9     9     -9
10     -9     88
12     8     0
Thanks

Hi,
Update < table name >
set column name = nvl(column name, -9),
column name = nvl(column name, -9)
Regards
Message was edited by:
Seshu

Updates using single SQL Update statement.

Hi Guys,
I had an interview... and was not able to give an answer of one of the question.
Given the emp table... need to update the salary with following requirement using one SQL statement...
1. Update salary+1000 for those employees who have salary between 500 and 1000
2. Update salary+500 for those employees who have salary between 1001 and 1500
Both above requirement should be done by using only one SQL update statement... can some one tell me how to do it?

update emp
set salary   = case when salary between 500 and 1000
                            then salary + 1000
                            when salary between 1001 and 1500
                            then salary + 500
                      end;Regards
Arun

Decode function in Update statement

Hello everyone,
I'm trying to write a query where I can update a pastdue_fees column in a book_trans table based on a difference between return_dte and due_dte columns.
I am using Oracle SQL. This is what I have so far for my decode function:
SQL> SELECT
2 DECODE(SIGN((return_dte - due_dte)*2),
3 '-1', '0',
4 '1', '12', 'Null')
5 FROM book_trans;
DECO
Null
12
Null
0
So the logic is that if the sign is -1, the value in return_dte column should be 0; if it's +1 then it's 12 and everything else is Null.
So now, I need to enter my decode function into the update statement to update the columns. However, I get error messages.
The logic should be:
UPDATE book_trans SET PastDue_fees = decode(expression)
I've given it a couple of different tries with the following results:
SQL> UPDATE book_trans
2 SET pastdue_fees = SELECT
3 DECODE(SIGN((return_dte - due_dte)*2),
4 '-1', '0',
5 '1', '12', 'Null')
6 FROM book_trans;
SET pastdue_fees = SELECT
ERROR at line 2:
ORA-00936: missing expression
SQL> UPDATE book_trans
2 SET pastdue_fees =
3 DECODE(SIGN((return_dte - due_dte)*2),
4 '-1', '0',
5 '1', '12', 'Null')
6 FROM book_trans;
FROM book_trans
ERROR at line 6:
ORA-00933: SQL command not properly ended
Any help or tips would be greatly appreciated as I've been taking SQL for about six weeks and not very proficient!
Thanks!

882300 wrote:
Hello everyone,
I'm trying to write a query where I can update a pastdue_fees column in a book_trans table based on a difference between return_dte and due_dte columns.
I am using Oracle SQL. This is what I have so far for my decode function:
SQL> SELECT
2 DECODE(SIGN((return_dte - due_dte)*2),
3 '-1', '0',
4 '1', '12', 'Null')
5 FROM book_trans;
DECO
Null
12
Null
0
So the logic is that if the sign is -1, the value in return_dte column should be 0; if it's +1 then it's 12 and everything else is Null.
So now, I need to enter my decode function into the update statement to update the columns. However, I get error messages.
The logic should be:
UPDATE book_trans SET PastDue_fees = decode(expression)
I've given it a couple of different tries with the following results:
SQL> UPDATE book_trans
2 SET pastdue_fees = SELECT
3 DECODE(SIGN((return_dte - due_dte)*2),
4 '-1', '0',
5 '1', '12', 'Null')
6 FROM book_trans;
SET pastdue_fees = SELECT
ERROR at line 2:
ORA-00936: missing expression
SQL> UPDATE book_trans
2 SET pastdue_fees =
3 DECODE(SIGN((return_dte - due_dte)*2),
4 '-1', '0',
5 '1', '12', 'Null')
6 FROM book_trans;
FROM book_trans
ERROR at line 6:
ORA-00933: SQL command not properly ended
Any help or tips would be greatly appreciated as I've been taking SQL for about six weeks and not very proficient!
Thanks!If you really really really want to update the entire table, the syntax would be...
UPDATE book_trans
SET
pastdue_fees = DECODE(SIGN((return_dte - due_dte)*2), -1, 0, 1, 12, Null);I took out all the single quotes. If you actually have a string column and you're storing entirely numbers in it then it should be declared as a NUMBER column and not a character (varchar2) column.
ALWAYS use the proper data type, it'll save you a ton of headaches in the future.
Also, since you're new to the forum, please read the FAQ so you learn the etiquette and what not.
http://wikis.sun.com/display/Forums/Forums+FAQ

Running an update statement on two dependent attributes

Dear All,
I have a repair_job table that contains values for work_cost, parts_cost and total_cost which is the sum of the work and parts cost values. I want to run an update statement that doubles the work cost and, naturally, updates the value of total cost as well. I tried to run it as:
update repair_job
set work_cost = 2 * work_cost, total_cost = work_cost + parts_cost
where licence in (
select licence from car
where year = to_char(sysdate,'YYYY')
thinking that because the update of work_cost is first on the list, the updated value of total cost would be correct. It seems however that the update of total cost happens first and then the work cost is been updated; not sure what the reason is for that and it happens no matter what the order is in the update statement.
I know that I can do it in two separate statements, or use a trigger or PL/SQL to do it but I am curious as to why it has this behaviour. Also, is there a way to do it in a single SQL statement - i.e. forcing the update of the work_cost attribute first and then that of total_cost?
I look forward to hearing from you soon.
Regards,
George

Welcome to the forum!
>
thinking that because the update of work_cost is first on the list, the updated value of total cost would be correct. It seems however that the update of total cost happens first and then the work cost is been updated; not sure what the reason is for that and it happens no matter what the order is in the update statement.
I know that I can do it in two separate statements, or use a trigger or PL/SQL to do it but I am curious as to why it has this behaviour. Also, is there a way to do it in a single SQL statement - i.e. forcing the update of the work_cost attribute first and then that of total_cost?
>
The update to all columns of the row happen at the same time - there is no order involved.
You don't need two statements but you do need to do the updates based on the current value of the columns.
set work_cost = 2 * work_cost, total_cost = 2 * work_cost + parts_cost----------
In addition to sb92075's comments in 11 g you could also just define a virtual column for total_cost and then just query it like you do now.
total_cost NUMBER GENERATED ALWAYS AS (work_cost + parts_cost) VIRTUAL,See this Oracle-base article for an example
http://www.oracle-base.com/articles/11g/virtual-columns-11gr1.php
Edited to supplement sb92075's reply by mentioning virtual columns

Use of ROWID in SQL Update Statement

Hi All,
I have an update statement which uses the rowid column to perform the selection on the target table. Given that a rowid represents the physical location of a row on disk we know that this reference can change when various activities are performed on the database/table/row etc...
Here is an example of the statement I am issuing:
UPDATE tabA outertab SET col1 = 'Value'
WHERE EXISTS (SELECT 1 FROM tabA innertab WHERE outertab.ROWID = outertab.ROWID AND ...)
Obviously the inner query is more complicated and uses other tables etc... but for the purposes of the example we dont need to include the detail.
My question is: When using rowid in a single SQL statement as a reference from a subquery to the outer statement is there a risk that external activities can change the rowid and those changes be reflected within the database session that my query is executing thus causing an inconsistency between the inner and outer SQL clause?
In response to the question which will follow this post: "Why don't you just use a PK", We would like to avoid maintaining a PK on the table as we are talking about very large volumes of data and we dont want to have to issue a call to a sequence if we can avoid it when we are inserting the data. If however there is a risk that this Update statement could fail or update the wrong rows then we may have to use a PK.
I know there is a lot of threads about this but I havnt been able to find one that someone has answered with any kind of confidence or clarity, any help would be much appreciated.
Thanks
Keith
Edited by: The Turtle on Mar 5, 2009 5:24 AM

When using rowid in a single SQL statement as a reference from a subquery to the outer statement is there a risk that external activities can change the rowid and those changes be reflected within the database session that my query is executing thus causing an inconsistency between the inner and outer SQL clause?No, it's safe to use rowid in this type of query. Docs
A row's assigned rowid remains unchanged unless the row is exported and imported using the Import and Export utilities. When you delete a row from a table and then commit the encompassing transaction, the deleted row's associated rowid can be assigned to a row inserted in a subsequent transaction.

Single update statement

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