How can I create a procedure to verify each row of a table and update a field according to the established statement?
I have 4 fields that I work with
SYS_UPDATE_PING
UPDATE_PING
PING_STATUS
TIME_OUT_PING
Here is my code:
create or replace procedure SP_DASHBOARD_PINGSTATUS is
begin
declare
sp_ping_final number;
BEGIN
Update rsmes.tb_op_pc_monitoring_v4 t
set t.sys_update_ping = sysdate;
for c in (select ((SYS_UPDATE_PING - UPDATE_PING)*60*60*24) as PING_RESULT into sp_ping_final from TB_OP_PC_MONITORING_V4)
loop
sp_ping_final := c.ping_result;
if c.ping_result <= 5 then
Update rsmes.tb_op_pc_monitoring_v4 tg
set tg.ping_status = 'OK',
tg.time_out_ping = sp_ping_final;
else
Update rsmes.tb_op_pc_monitoring_v4 tn
set tn.ping_status = 'NG',
tn.time_out_ping = sp_ping_final;
end if;
end loop;
commit;
END;
end SP_DASHBOARD_PINGSTATUS;
I make a time difference between SYS_UPDATE_PING and UPDATE_PING, if the result in seconds is less than 5 it must update the PING_STATUS field to OK and put the seconds difference in TIME_OUT_PING, otherwise it will update NG and put the seconds difference in TIME_OUT_PING,
I want it to compare on each row but it updates me on all fields instead of one by one.
I know I'm forgetting something but could you help me find my fault and know the solution?
Thank you
That's because UPDATE statements miss the WHERE clause. Without it, you're always updating all rows in the table.
It means that cursor should contain some kind of an ID, which you'll the reuse in UPDATE. For example:
for c in (select id, --> this
((sys_update_ping - ...)
) loop
...
update tb_op_pc_monitoring_v4 tg set
tg.ping_status = 'OK'
where tg.id = c.id; --> this
...
end loop;
Also, you don't SELECT INTO in cursor. Remove the sp_ping_final entirely.
Finally, I'd say that you don't need PL/SQL (loop especially) at all. The whole code you wrote can be rewritten into a single
UPDATE tb_op_pc_monitoring_v4 tg
SET tg.ping_status =
CASE
WHEN (SYSDATE - tg.update_ping) * 60 * 60 * 24 <= 5 THEN 'OK'
ELSE 'NG'
END,
tg.time_out_ping = (SYSDATE - tg.update_ping) * 60 * 60 * 24;
which should work way faster than your row-by-row processing.
Related
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;
Here in my oracle apex report i am having 2 apex_items ,checkbox and textfield..
I need to insert the records which is checked in report if I have selected 5 checkbox then it should insert all the 5 records, currently only one record is getting inserting, please help..
SQL in interactive report query:
select APEX_ITEM.CHECKBOX(1,pdcq.CHEQUE_NUMBER)"SELECT",
pdc.CUST_NAME ,pdr.RECEIPT_NUMBER ,pdcq.INSTALLMENT,
pdcq.CHEQUE_NUMBER,pdcq.CHEQUE_AMOUNT, APEX_ITEM.TEXT(2,null) Remarks
from pdc_customer pdc,pdc_receipt pdr,pdc_cheques pdcq
where pdc.CUST_ID=pdr.CUST_ID and pdc.CUST_ID=pdcq.CUST_ID and pdcq.status='Pending' AND pdcq.RECEIPT_NUMBER=pdr.receipt_number
and pdcq.APPROVER=NVL(SYS_CONTEXT('APEX$SESSION','APP_USER'), USER)
Code
begin
select NVL(SYS_CONTEXT('APEX$SESSION','APP_USER'), USER) into v_user from dual;
FOR I in 1 ..APEX_APPLICATION.G_f01.COUNT
LOOP
FOR J in 1 ..APEX_APPLICATION.G_f02.COUNT
LOOP
UPDATE PDC_STATUS_HISTORY SET STATUS='Approved',
REMARKS=APEX_APPLICATION.G_F02(j),
APPROVED_DATE=sysdate ,
APPROVED_BY=v_user
WHERE APPROVAL_LEVEL=1 and
CHEQUE_NUMBER=APEX_APPLICATION.G_f01(i);
END LOOP;
END LOOP;
end;
The issue you're probably running into is the following. The array for the checkbox only contains elements for the selected rows, whereas the array for the text element will contain an element for every row. So the index for the selected rows will not match the text row if not all checkboxes are checked. To work around that you can add a 3rd column of type APEX_ITEM.HIDDEN
select
APEX_ITEM.CHECKBOX(1,pdcq.CHEQUE_NUMBER)"SELECT",
pdc.CUST_NAME ,
...
APEX_ITEM.TEXT(2,null) Remarks,
APEX_ITEM.HIDDEN(3,pdcq.CHEQUE_NUMBER) hidden_checkno
from pdc_customer pdc
JOIN pdc_receipt pdr ON pdc.CUST_ID=pdr.CUST_ID
...
The process would then become:
BEGIN
FOR I in 1 ..APEX_APPLICATION.G_f01.COUNT
LOOP
FOR J in 1 ..APEX_APPLICATION.G_f03.COUNT
LOOP
IF APEX_APPLICATION.G_F01(i) = APEX_APPLICATION.G_F03(j) THEN
UPDATE PDC_STATUS_HISTORY
SET STATUS='Approved',
REMARKS=APEX_APPLICATION.G_F02(j),
APPROVED_DATE=sysdate ,
APPROVED_BY=NVL(SYS_CONTEXT('APEX$SESSION','APP_USER'), USER)
WHERE APPROVAL_LEVEL = 1 AND
CHEQUE_NUMBER = APEX_APPLICATION.G_f01(i);
END IF;
END LOOP;
END LOOP;
END;
Note1: The SELECT FROM DUAL is not needed, you can use that expression in your update statement directly.
Note2: Use ANSI JOIN style syntax instead of the very very old oracle syntax.
I will try to present my problem as simplified as possible.
Assume that we have 3 tables in Oracle 11g.
Persons (person_id, name, surname, status, etc )
Actions (action_id, person_id, action_value, action_date, calculated_flag)
Calculations (calculation_id, person_id,computed_value,computed_date)
What I want is for each person that meets certain criteria (let's say status=3)
I should get the sum of action_values from the Actions table where calculated_flag=0. (something like this select sum(action_value) from Actions where calculated_flag=0 and person_id=current_id).
Then I shall use that sum in a some kind of formula and update the Calculations table for that specific person_id.
update Calculations set computed_value=newvalue, computed_date=sysdate
where person_id=current_id
After that calculated_flag for participated rows will be set to 1.
update Actions set calculated_flag=1
where calculated_flag=0 and person_id=current_id
Now this can be easily done sequentially, by creating a cursor that will run through Persons table and then execute each action needed for the specific person.
(I don't provide the code for the sequential solution as the above is just an example that resembles my real-world setup.)
The problem is that we are talking about quite big amount of data and sequential approach seems like a waste of computational time.
It seems to me that this task could be performed in parallel for number of person_ids.
So the question is:
Can this kind of task be performed using parallelization in PL/SQL?
What would the solution look like? That is, what special packages (e.g. DBMS_PARALLEL_EXECUTE), keywords (e.g. bulk collect), methods should be used and in what manner?
Also, should I have any concerns about partial failure of parallel updates?
Note that I am not quite familiar with parallel programming with PL/SQL.
Thanks.
Edit 1.
Here my pseudo code for my sequential solution
procedure sequential_solution is
cursor persons_of_interest is
select person_id from persons
where status = 3;
tempvalue number;
newvalue number;
begin
for person in persons_of_interest
loop
begin
savepoint personsp;
--step 1
select sum(action_value) into tempvalue
from actions
where calculated_flag = 0
and person_id = person.person_id;
newvalue := dosomemorecalculations(tempvalue);
--step 2
update calculations set computed_value = newvalue, computed_date = sysdate
where person_id = person.person_id;
--step 3
update actions set calculated_flag = 1;
where calculated_flag = 0 and person_id = person.person_id;
--step 4 (didn't mention this step before - sorry)
insert into actions
( person_id, action_value, action_date, calculated_flag )
values
( person.person_id, 100, sysdate, 0 );
exception
when others then
rollback to personsp;
-- this call is defined with pragma AUTONOMOUS_TRANSACTION:
log_failure(person_id);
end;
end loop;
end;
Now, how would I speed up the above either with forall and bulk colletct or with parallel programming Under the following constrains:
proper memory management (taking into consideration large amount of data)
For a single person if one part of the step sequence fails - all steps should be rolled back and the failure logged.
I can propose the following. Let's say you have 1 000 000 rows in persons table, and you want to process 10 000 persons per iteration. So you can do it in this way:
declare
id_from persons.person_id%type;
id_to persons.person_id%type;
calc_date date := sysdate;
begin
for i in 1 .. 100 loop
id_from := (i - 1) * 10000;
id_to := i * 10000;
-- Updating Calculations table, errors are logged into err$_calculations table
merge into Calculations c
using (select p.person_id, sum(action_value) newvalue
from Actions a join persons p on p.person_id = a.person_id
where a.calculated_flag = 0
and p.status = 3
and p.person_id between id_from and id_to
group by p.person_id) s
on (s.person_id = c.person_id)
when matched then update
set c.computed_value = s.newvalue,
c.computed_date = calc_date
log errors into err$_calculations reject limit unlimited;
-- updating actions table only for those person_id which had no errors:
merge into actions a
using (select distinct p.person_id
from persons p join Calculations c on p.person_id = c.person_id
where c.computed_date = calc_date
and p.person_id between id_from and id_to)
on (c.person_id = p.person_id)
when matched then update
set a.calculated_flag = 1;
-- inserting list of persons for who calculations were successful
insert into actions (person_id, action_value, action_date, calculated_flag)
select distinct p.person_id, 100, calc_date, 0
from persons p join Calculations c on p.person_id = c.person_id
where c.computed_date = calc_date
and p.person_id between id_from and id_to;
commit;
end loop;
end;
How it works:
You split the data in persons table into chunks about 10000 rows (depends on gaps in numbers of ID's, max value of i * 10000 should be knowingly more than maximal person_id)
You make a calculation in the MERGE statement and update the Calculations table
LOG ERRORS clause prevents exceptions. If an error occurs, the row with the error will not be updated, but it will be inserted into a table for errors logging. The execution will not be interrupted. To create this table, execute:
begin
DBMS_ERRLOG.CREATE_ERROR_LOG('CALCULATIONS');
end;
The table err$_calculations will be created. More information about DBMS_ERRLOG package see in the documentation.
The second MERGE statement sets calculated_flag = 1 only for rows, where no errors occured. INSERT statement inserts the these rows into actions table. These rows could be found just with the select from Calculations table.
Also, I added variables id_from and id_to to calculate ID's range to update, and the variable calc_date to make sure that all rows updated in first MERGE statement could be found later by date.
I am converting some code in Access over to Oracle, and one of the queries in Access uses a table that I am unable to use in Oracle. I am unable to create new tables, so I am trying to figure out a way to use the logic behind the table in the FOR section of my select.
The logic of the table is similar to:
FOR i = 1 To 100
number = number + 1
.AddNew
!tbl_number = number
NEXT i
I'm trying to convert this to oracle, and so far I have:
FOR i in 1 .. 100 LOOP
number := number + 1;
--This is where I am stuck; How do I simulate the table part
END LOOP;
I was thinking a cursor or a record would be the answer, but I can't seem to figure out how to implement that. In the end I basically want to have:
SELECT
table.number
FROM
(
--My for loop logic
) table
EDIT
The calculation is a bit more complicated; that was just an example. They aren't actually sequential, and there isn't really a pattern to rows.
EDIT
Here is a more complicated version of the for loop which is closer to what I'm actually doing:
FOR i in 1 .. 100 LOOP
number1 := number1 + 7;
number2 := (number2 + 8) / number1;
--This is where I am stuck; How do I simulate the table part
END LOOP;
You could use a recursive query (assuming you are on Oralce 11gR2 or later):
with example(idx, number1, number2) as (
-- Anchor Section
select 1
, 1 -- initial value
, 2 -- initial value
from dual
union all
-- Recursive Section
select prev.idx + 1
, prev.number1 + 7
, (prev.number2 + 8) / prev.number1
from example prev
where prev.idx < 100 -- The Guard
)
select * from example;
In the Anchor section set all the values for your first record. Then in the Recursive section setup the logic to determine the next records values as a function of the prior records values.
The Anchor section could select the initial values from some other table rather than being hard coded as in my example.
The recursive section needs to select from the named subquery (in this case example) but may also join to other tables as needed.
You need to generate a set with sequential integer numbers. Maybe you can use this (for Oracle 10g and above):
SELECT
ROWNUM NUM
FROM
DUAL D1,
DUAL D2
CONNECT BY
(D1.DUMMY = D2.DUMMY AND ROWNUM <= 100)
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)