The UPSERT operation either updates or inserts a row in a table, depending if the table already has a row that matches the data:
if table t has a row exists that has key X:
update t set mystuff... where mykey=X
else
insert into t mystuff...
Since Oracle doesn't have a specific UPSERT statement, what's the best way to do this?
The MERGE statement merges data between two tables. Using DUAL
allows us to use this command. Note that this is not protected against concurrent access.
create or replace
procedure ups(xa number)
as
begin
merge into mergetest m using dual on (a = xa)
when not matched then insert (a,b) values (xa,1)
when matched then update set b = b+1;
end ups;
/
drop table mergetest;
create table mergetest(a number, b number);
call ups(10);
call ups(10);
call ups(20);
select * from mergetest;
A B
---------------------- ----------------------
10 2
20 1
The dual example above which is in PL/SQL was great becuase I wanted to do something similar, but I wanted it client side...so here is the SQL I used to send a similar statement direct from some C#
MERGE INTO Employee USING dual ON ( "id"=2097153 )
WHEN MATCHED THEN UPDATE SET "last"="smith" , "name"="john"
WHEN NOT MATCHED THEN INSERT ("id","last","name")
VALUES ( 2097153,"smith", "john" )
However from a C# perspective this provide to be slower than doing the update and seeing if the rows affected was 0 and doing the insert if it was.
An alternative to MERGE (the "old fashioned way"):
begin
insert into t (mykey, mystuff)
values ('X', 123);
exception
when dup_val_on_index then
update t
set mystuff = 123
where mykey = 'X';
end;
Another alternative without the exception check:
UPDATE tablename
SET val1 = in_val1,
val2 = in_val2
WHERE val3 = in_val3;
IF ( sql%rowcount = 0 )
THEN
INSERT INTO tablename
VALUES (in_val1, in_val2, in_val3);
END IF;
insert if not exists
update:
INSERT INTO mytable (id1, t1)
SELECT 11, 'x1' FROM DUAL
WHERE NOT EXISTS (SELECT id1 FROM mytble WHERE id1 = 11);
UPDATE mytable SET t1 = 'x1' WHERE id1 = 11;
None of the answers given so far is safe in the face of concurrent accesses, as pointed out in Tim Sylvester's comment, and will raise exceptions in case of races. To fix that, the insert/update combo must be wrapped in some kind of loop statement, so that in case of an exception the whole thing is retried.
As an example, here's how Grommit's code can be wrapped in a loop to make it safe when run concurrently:
PROCEDURE MyProc (
...
) IS
BEGIN
LOOP
BEGIN
MERGE INTO Employee USING dual ON ( "id"=2097153 )
WHEN MATCHED THEN UPDATE SET "last"="smith" , "name"="john"
WHEN NOT MATCHED THEN INSERT ("id","last","name")
VALUES ( 2097153,"smith", "john" );
EXIT; -- success? -> exit loop
EXCEPTION
WHEN NO_DATA_FOUND THEN -- the entry was concurrently deleted
NULL; -- exception? -> no op, i.e. continue looping
WHEN DUP_VAL_ON_INDEX THEN -- an entry was concurrently inserted
NULL; -- exception? -> no op, i.e. continue looping
END;
END LOOP;
END;
N.B. In transaction mode SERIALIZABLE, which I don't recommend btw, you might run into
ORA-08177: can't serialize access for this transaction exceptions instead.
I'd like Grommit answer, except it require dupe values. I found solution where it may appear once: http://forums.devshed.com/showpost.php?p=1182653&postcount=2
MERGE INTO KBS.NUFUS_MUHTARLIK B
USING (
SELECT '028-01' CILT, '25' SAYFA, '6' KUTUK, '46603404838' MERNIS_NO
FROM DUAL
) E
ON (B.MERNIS_NO = E.MERNIS_NO)
WHEN MATCHED THEN
UPDATE SET B.CILT = E.CILT, B.SAYFA = E.SAYFA, B.KUTUK = E.KUTUK
WHEN NOT MATCHED THEN
INSERT ( CILT, SAYFA, KUTUK, MERNIS_NO)
VALUES (E.CILT, E.SAYFA, E.KUTUK, E.MERNIS_NO);
I've been using the first code sample for years. Notice notfound rather than count.
UPDATE tablename SET val1 = in_val1, val2 = in_val2
WHERE val3 = in_val3;
IF ( sql%notfound ) THEN
INSERT INTO tablename
VALUES (in_val1, in_val2, in_val3);
END IF;
The code below is the possibly new and improved code
MERGE INTO tablename USING dual ON ( val3 = in_val3 )
WHEN MATCHED THEN UPDATE SET val1 = in_val1, val2 = in_val2
WHEN NOT MATCHED THEN INSERT
VALUES (in_val1, in_val2, in_val3)
In the first example the update does an index lookup. It has to, in order to update the right row. Oracle opens an implicit cursor, and we use it to wrap a corresponding insert so we know that the insert will only happen when the key does not exist. But the insert is an independent command and it has to do a second lookup. I don't know the inner workings of the merge command but since the command is a single unit, Oracle could execute the correct insert or update with a single index lookup.
I think merge is better when you do have some processing to be done that means taking data from some tables and updating a table, possibly inserting or deleting rows. But for the single row case, you may consider the first case since the syntax is more common.
A note regarding the two solutions that suggest:
1) Insert, if exception then update,
or
2) Update, if sql%rowcount = 0 then insert
The question of whether to insert or update first is also application dependent. Are you expecting more inserts or more updates? The one that is most likely to succeed should go first.
If you pick the wrong one you will get a bunch of unnecessary index reads. Not a huge deal but still something to consider.
Try this,
insert into b_building_property (
select
'AREA_IN_COMMON_USE_DOUBLE','Area in Common Use','DOUBLE', null, 9000, 9
from dual
)
minus
(
select * from b_building_property where id = 9
)
;
From http://www.praetoriate.com/oracle_tips_upserts.htm:
"In Oracle9i, an UPSERT can accomplish this task in a single statement:"
INSERT
FIRST WHEN
credit_limit >=100000
THEN INTO
rich_customers
VALUES(cust_id,cust_credit_limit)
INTO customers
ELSE
INTO customers SELECT * FROM new_customers;
My statement:
SELECT ROW_ID DATA_T WHERE CITY_ID=2000 AND IS_FREE=0 AND ROWNUM = 1
is used to retrieve the first row for a db table that has many entries with CITY_ID equal to 2000.
The ROW_ID that is returned is then used in an UPDATE statement in order to use this row and set IS_FREE=1.
That worked very well until two threads called the SELECT statement and the got the same ROW_ID obviously... That is my problem in a few words.
I am using ORACLE DB (12.x)
How do I resolve the problem? Can I use FOR UPDATE in this case?
I want every "client" somehow to get a different row or at least lock on of them
Something like this
function get_row_id return number
as
cursor cur_upd is
SELECT ROW_ID FROM TB WHERE CITY_ID=2000 AND IS_FREE=0 AND ROWNUM = 1
FOR UPDATE SKIP LOCKED;
begin
for get_cur_upd in cur_upd
loop
update TB
set IS_FREE = 1
where ROW_ID = get_cur_upd.ROW_ID;
commit work;
return get_cur_upd.ROW_ID;
end loop;
return null;
end;
commit or not after update depends on your logic.
Also you can return row_id without update&commit and do it later outside func.
I have the following query that I am using in Oracle 11g
IF EXISTS (SELECT * FROM EMPLOYEE_MASTER WHERE EMPID='ABCD32643')
THEN
update EMPLOYEE_MASTER set EMPID='A62352',EMPNAME='JOHN DOE',EMPTYPE='1' where EMPID='ABCD32643' ;
ELSE
insert into EMPLOYEE_MASTER(EMPID,EMPNAME,EMPTYPE) values('A62352','JOHN DOE','1') ;
END IF;
On running the statement I get the following output:
Error starting at line : 4 in command -
ELSE
Error report -
Unknown Command
1 row inserted.
Error starting at line : 6 in command -
END IF
Error report -
Unknown Command
The values get inserted with error when I run it directly. But when I try to execute this query through my application I get an oracle exception because of the error generated :
ORA-00900: invalid SQL statement
And hence the values are not inserted.
I am relatively new to Oracle. Please advise on what's wrong with the above query so that I could run this query error free.
If MERGE doesn't work for you, try the following:
begin
update EMPLOYEE_MASTER set EMPID='A62352',EMPNAME='JOHN DOE',EMPTYPE='1'
where EMPID='ABCD32643' ;
if SQL%ROWCOUNT=0 then
insert into EMPLOYEE_MASTER(EMPID,EMPNAME,EMPTYPE)
values('A62352','JOHN DOE','1') ;
end if;
end;
Here you you the update on spec, then check whether or not you found a matching row, and insert in case you didn't.
"what's wrong with the above query "
What's wrong with the query is that it is not a query (SQL). It should be a program snippet (PL/SQL) but it isn't written as PL/SQL block, framed by BEGIN and END; keywords.
But turning it into an anonymous PL/SQL block won't help. Oracle PL/SQL does not support IF EXISTS (select ... syntax.
Fortunately Oracle SQL does support MERGE statement which does the same thing as your code, with less typing.
merge into EMPLOYEE_MASTER em
using ( select 'A62352' as empid,
'JOHN DOE' as empname,
'1' as emptype
from dual ) q
on (q.empid = em.empid)
when not matched then
insert (EMPID,EMPNAME,EMPTYPE)
values (q.empid, q.empname, q.emptype)
when matched then
update
set em.empname = q.empname, em.emptype = q.emptype
/
Except that you're trying to update empid as well. That's not supported in MERGE. Why would you want to change the primary key?
"Does this query need me to add values to all columns in the table? "
The INSERT can have all the columns in the table. The UPDATE cannot change the columns used in the ON clause (usually the primary key) because that's a limitation of the way MERGE works. I think it's the same key preservation mechanism we see when updating views. Find out more.
Why am I getting this error and what does it mean by no statement parsed.
ORA-01003: no statement parsed
Here is the code:
PROCEDURE ORIGINAL_TABLE.UPDATE_GROUPS IS
-- cursor loaded with the swam groups
CURSOR cursor1 IS
SELECT ID, NEW_DESCRIPTION
FROM NEW_TABLE.NEW_GROUP_TABLE#DB_LINK.X;
BEGIN
FOR C1_REC IN cursor1 LOOP
UPDATE
ORIGINAL_TABLE."GROUPS"
SET
GROUP_ID = C1_REC.ID
WHERE
ORIGINAL_TABLE."GROUPS".DESCRIPTION = C1_REC.NEW_DESCRIPTION;
IF (SQL%ROWCOUNT = 0) THEN
INSERT INTO
ORIGINAL_TABLE.GROUPS("GROUP_ID", "DESCRIPTION")
VALUES (C1_REC.ID, C1_REC.NEW_DESCRIPTION);
END IF;
END LOOP;
EXCEPTION
WHEN OTHERS THEN
dbms_output.put_line(SQLERRM);
END;
What I try to do with the code above is to update and old table with the values from a new table and in case that the new group doesn't exist insert it.
Update: Changed %ROWCOUNT > 0 for %ROWCOUNT = 0
Use MERGE statement, it does update/insert stuff more efficiently and pay attention your plsql doesn't provide it is intended for. It tries to make an update statement and if a record found it inserts another record. In order to fix it use
IF (SQL%ROWCOUNT = 0)
I presume the reason of the issue is the . in DBLINK name.
Moreover I would suggest to get rid of quotes for tables/fields just in case as well as schema name.
Another words delete all ORIGINAL_TABLE.
merge into groups g
using (
SELECT ID, NEW_DESCRIPTION
FROM NEW_TABLE.NEW_GROUP_TABLE#DB_LINK.X
) nt
on (nt.NEW_DESCRIPTION = g.description )
when matched then update set g.group_id = nt.id
when non matched then insert(GROUP_ID, DESCRIPTION)
values(nt.id, nt.NEW_DESCRIPTION)
There are plenty of stored procedure on 10g platform . ( Almost 500 SPs)
Each SP might have loop, fetch and etc.
I'd like to ask you if there is a cool method to control all the SPs which are currently running on 10g, and guarantee that it works on 11 g.
I have a development server 1 which is 10 g and the other development server is 11 g.
I can use both of them to testify the propose above.
For instance I know that on 10 g if you use loop, and during the loop the update statements do not affect the loop data but 11g.
There might be more cases that I have to consider. Please tell me if you have any brillant idea , otherwise I will check them up one by one manually and it is a lot of time and human control might be weak sometimes.
important note: It is said that if you select some data from a table or tables, and if you use it in a loop, then during de loop, if you update and commit between loop case, it affects the selected data in cursor.(#11g) But this did not happen #10g version. Please correct me if you heard something like that.
The Example Case;
CREATE TABLE vty_musteri(
musterino NUMBER NOT NULL,
subeadi VARCHAR2(61),
kayitzamani VARCHAR2(20)
);
INSERT INTO vty_musteri (musterino, subeadi, kayitzamani )
VALUES (12345, 'AMSTERDAM', '05/30/2012 15:11:13');
COMMIT;
CREATE UNIQUE INDEX vty_musteri_idx ON vty_musteri (musterino);
SELECT * FROM vty_musteri;
CREATE OR REPLACE PROCEDURE krd_upd_silseomusteri_sp(RC1 in out SYS_REFCURSOR) AS
v_musterino NUMBER := 12345;
BEGIN
OPEN RC1 FOR
SELECT m.musterino, m.subeadi, m.kayitzamani
FROM vty_musteri m
WHERE m.musterino = v_musterino;
update vty_musteri
set subeadi = 'PORTO',
kayitzamani = (SELECT TO_CHAR(SYSDATE, 'MM/DD/YYYY HH24:MI:SS')
FROM dual)
where musterino = v_musterino;
COMMIT;
After all run this test on PLSQL:
DECLARE
--test
vRecTip SYS_REFCURSOR;
TYPE vRecTipK IS RECORD(
musterino NUMBER,
subeadi VARCHAR2(61),
kayitzamani VARCHAR2(20)
);
v_SeoTip vRecTipK;
BEGIN
krd_upd_silseomusteri_sp(rc1 => vRecTip);
IF vRecTip%ISOPEN THEN
LOOP
FETCH vRecTip
INTO v_SeoTip;
EXIT WHEN vRecTip%NOTFOUND;
dbms_output.put_line('The Value : ' || v_SeoTip.musterino || ' - ' || v_SeoTip.subeadi || ' - ' || v_SeoTip.kayitzamani);
END LOOP;
END IF;
COMMIT;
END;
END;
If you run this on 10g you will see AMSTERDAM, but on 11G, it is PORTO.
To fix it; I put a hint in the sp like the following:
SELECT /*+ full(m)*/ m.musterino, m.subeadi, m.kayitzamani
Isn't it weird? any alternative sugesstion to get AMSTERDAM ?
One thing we stumbled upon during a migration were queries that weren't supposed to work on 10.x (but did anyway) did no longer work on 11.x
This happens if you have ambigous column references in your query.
Something like this:
SELECT name,
f.some_col,
b.other_col
FROM foo f,
JOIN bar b ON f.id = b.fid
If the column name exists in both tables, 10.x would run the statement - which was a bug.
This bug (BugID: 6760937) was fixed and makes the statement (rightfully) fail in 11.x
Basic PLSQL structures should work exactly the same. Some pitfalls are listed here:
http://www.help2ora.com/index.php/2011/08/04/be-careful-when-migrating-difference-between-oracle-10g-and-11g/
To fix it; I put a hint in the sp like the following:
SELECT /+ full(m)/ m.musterino, m.subeadi, m.kayitzamani
Recently I have done migration to Oracle 11g. Faced few unprecedented issues. I have written a blog post on this. Have a look http://learncodewrite.blogspot.in/2017/04/migrating-to-oracle-11g-from-oracle-10g.html?m=1.