Oracle Cursor Is Not Working as Expected - oracle

Here is the procedure,
CREATE OR REPLACE PROCEDURE provsnXmlCmprsn (
encyNo SAS_PRO_CTL.AGENCYNO%TYPE, period SAS_PRO_CTL.PERIODE%TYPE) IS
xmlContent SAS_PRO_XML.XMLCONTENT%TYPE;
sasProvisionId SAS_PRO_CTL.SASPROVISIONID%TYPE;
CURSOR crsrXml IS
SELECT XMLCONTENT, c.SASPROVISIONID FROM SAS_PRO_XML x, SAS_PRO_CTL c
WHERE x.SASPROVISIONID = c.SASPROVISIONID AND c.PERIODE = period
AND c.AGENCYNO = agencyNo ORDER BY XMLLINENO;
BEGIN
DBMS_OUTPUT.put_line('Params: ' || agencyNo || ', ' || period);
OPEN crsrXml;
LOOP
FETCH crsrXml INTO xmlContent, sasProvisionId;
EXIT WHEN crsrXml%NOTFOUND;
DBMS_OUTPUT.put_line('XML Content Length: ' || LENGTH(xmlContent));
END LOOP;
CLOSE crsrXml;
END provsnXmlCmprsn;
The query in the cursor is retrieving 5 rows, whereas 1 row is expected, according to the condition and argument values. The same query results in 1 row, when run independently. And the surprising part is, the query in the cursor always return 5 rows no matter if the condition, c.PERIODE = period AND c.AGENCYNO = agencyNo, passed or not. Which clearly means that this query,
SELECT XMLCONTENT, c.SASPROVISIONID FROM SAS_PRO_XML x, SAS_PRO_CTL c
WHERE x.SASPROVISIONID = c.SASPROVISIONID AND c.PERIODE = period
AND c.AGENCYNO = agencyNo ORDER BY XMLLINENO;
and this query,
SELECT XMLCONTENT, c.SASPROVISIONID FROM SAS_PRO_XML x, SAS_PRO_CTL c
WHERE x.SASPROVISIONID = c.SASPROVISIONID ORDER BY XMLLINENO;
are behaving same inside the cursor. This, AND c.PERIODE = period AND c.AGENCYNO = agencyNo, part is not at all considered. Any idea what's going wrong?

One of your parameters has the same name as the column: AGENCYNO. Because of the way scoping works this evaluates to 1=1. This is why it is good practice to give parameters unique names, for example by prepending them with p_.
You should find that
AND c.PERIODE = p_period AND c.AGENCYNO = p_agencyNo
returns the desired one row. Strictly speaking you don't need to change the name of period to p_period because it is already distinguished from periode. But consistency is a virtue in software engineering.

Related

basic variables returning all results

I have the below variable.
DECLARE
v_clt NUMBER;
BEGIN
DBMS_OUTPUT.PUT_LINE(v_clt);
END;
/
SELECT *
FROM CCP
WHERE CCP.ID = &v_clt
--AND CASE WHEN &v_clt < 1 THEN ID ELSE &v_clt END ID
I have may sub-queries within my query and I would like to be able to test the query by adding in one value for each sub queries, hence the variable and it works.
I also would like to be able to return all results at any given point too. Can this be accomplished?
You can use special value as 0 combine with decode (or case) to view all results
WHERE CCP.ID = decode(&v_clt,0,CCP.ID,&v_clt )

Oracle SQL Selecting weekly music rank procedure

I'm trying to make procedure to select weekly music rank based on hits and likes.
create or replace procedure select_rank(
v_title IN music.title%TYPE,
v_release_date IN music.release_date%TYPE,
v_hit IN music.hit%TYPE
) is
v_cnt number := 0;
BEGIN
select music.title, music.release_date, count(melon_user.user_idx) as likes, music.hit
into v_rank, v_title, v_cnt, v_release_date, v_hit
from melon_user, user_like_music, music
where melon_user.user_idx = user_like_music.user_idx
and user_like_music.music_idx = music.music_idx
group by music.title, music.hit, music.release_date
order by count(melon_user.user_idx) desc, music.hit desc;
DBMS_OUTPUT.PUT_LINE('v_title: ' || v_title);
DBMS_OUTPUT.PUT_LINE('v_cnt: ' || v_cnt);
DBMS_OUTPUT.PUT_LINE('v_release_date: ' || v_release_date);
DBMS_OUTPUT.PUT_LINE('v_hit: ' || v_hit);
END select_rank;
/
But I keep getting error says
PLS-00403: expression 'V_RELEASE_DATE' cannot be used as an
INTO-target of a SELECT/FETCH statement
PLS-00403: expression 'V_RELEASE_DATE' cannot be used as an
INTO-target of a SELECT/FETCH statement
PLS-00403: expression 'V_RELEASE_DATE' cannot be used as an
INTO-target of a SELECT/FETCH statement
how do I fix this?
In the procedure's signature you have:
v_release_date IN music.release_date%TYPE,
v_release_date is an IN parameter and will be read only. If you want to assign values to it wthin the procedure and return them then make it an OUT (or IN OUT) parameter.
However, you have also:
Not declared the v_rank variable.
Your query appears likely to return multiple rows - SELECT .. INTO .. will only work for queries that return a single row. If this is the case then you either want to use BULK COLLECT INTO or return a cursor.

Ref Cursor Exceptions

I have a couple of questions arounbd ref_cursors. Below is a ref_cursor that returns a a single row to a Unix calling script based on what is passed in and although the select looks a little untidy, it works as expected.
My first question is that in the select I join to a lookup table to retrieve a single lookup value 'trigram' and on testing found that this join will occasionally fail as no value exists. I have tried to capture this with no_data_found and when others exception but this does not appear to be working.
Ideally if the join fails I would still like to return the values to the ref_cursor but add something like 'No Trigram' into the trigram field - primarily I want to capture exception.
My second question is more general about ref_cursors - While initially I have created this in its own procedure, it is likely to get called by the main processing procedure a number of times, one of the conditions requires a seperate select but the procedure would only ever return one ref_cur when called, can the procdure ref_cur out be associated with 2 queries.
CREATE OR REPLACE PROCEDURE OPC_OP.SiteZone_status
(in_site_id IN AW_ACTIVE_ALARMS.site_id%TYPE
,in_zone_id IN AW_ACTIVE_ALARMS.zone_id%TYPE
,in_mod IN AW_ACTIVE_ALARMS.module%TYPE
,p_ResultSet OUT TYPES.cursorType
)
AS
BEGIN
OPEN p_ResultSet FOR
SELECT a.site_id,'~',a.zone_id,'~',b.trigram,'~',a.module,'~',a.message_txt,'~',a.time_stamp
FROM AW_ACTIVE_ALARMS a, AW_TRIGRAM_LOCATION b
WHERE a.site_id = b.site_id
AND a.zone_id = b.zone_id
AND a.site_id = in_site_id
AND a.zone_id = in_zone_id
AND a.module LIKE substr(in_mod,1,3)||'%'
AND weight = (select max(weight) from AW_ACTIVE_ALARMS c
WHERE c.site_id = in_site_id
AND c.zone_id = in_zone_id
AND c.module LIKE substr(in_mod,1,3)||'%');
EXCEPTION
WHEN OTHERS
THEN
DBMS_OUTPUT.PUT_LINE('No Data Found');
END SiteZone_status;
I have modified my code to adopt answers provided and this now works as expected as a standalone procedure within my package, which when called via a UNIX script using:
v_process_alarm=$(sqlplus -s user/pass <
set colsep ','
set linesize 500
set pages 0 feedback off;
set serveroutput on;
VARIABLE resultSet REFCURSOR
EXEC alarm_pkg.rtn_active_alarm($site,$zone,$module, :resultSet);
PRINT :resultSet
EOF
)
However the procedure returning the ref cursor is to be called from the main processing procedure as I only want to return values if certain criteria are met. I have add an out refcurosr to my main procedure and set a variable to match, I then call my ref cursor procedure from here but this fails to compile
with the message 'Wrong number or types of argument in call'
My question is what is the correct way to call a procedure that has out refcursor from within a procedure and then return these values from there back to the calling script.
Oracle doesn't know whether a query will return rows until you fetch from the cursor. And it is not an error for a query to return 0 rows. So you will never get a no_data_found exception from opening a cursor. You'll only get that if you do something like a select into a local variable in which case a query that returns either 0 or more than 1 row is an error.
It sounds like you want to do an outer join to the AW_TRIGRAM_LOCATION table rather than a current inner join. This will return data from the other tables even if there is no matching row in aw_trigram_location. That would look something like this (I have no idea why every other column is a hard-coded tilde character, that seems exceptionally odd)
SELECT a.site_id,'~',
a.zone_id,'~',
nvl(b.trigram, 'No Trigram Found'),'~',
a.module,'~',
a.message_txt,'~',
a.time_stamp
FROM AW_ACTIVE_ALARMS a
LEFT OUTER JOIN AW_TRIGRAM_LOCATION b
ON( a.site_id = b.site_id AND
a.zone_id = b.zone_id )
WHERE a.site_id = in_site_id
AND a.zone_id = in_zone_id
AND a.module LIKE substr(in_mod,1,3)||'%'
AND weight = (select max(weight)
from AW_ACTIVE_ALARMS c
WHERE c.site_id = in_site_id
AND c.zone_id = in_zone_id
AND c.module LIKE substr(in_mod,1,3)||'%');
I'm not quite sure that I understand your last question. You can certainly put logic in your procedure to run a different query depending on an input parameter. Something like
IF( <<some condition>> )
THEN
OPEN p_ResultSet FOR <<query 1>>
ELSE
OPEN p_ResultSet FOR <<query 2>>
END IF;
Whether it makes sense to do this rather than adding additional predicates or creating separate procedures is a question you'd have to answer.
You can use a left outer join to your look-up table, which is clearer if you use ANSI join syntax rather than Oracle's old syntax. If there is no record in AW_TRIGRAM_LOCATION then b.trigram will be null, and you can then use NVL to assign a dummy value:
OPEN p_ResultSet FOR
SELECT a.site_id,'~',a.zone_id,'~',NVL(b.trigram, 'No Trigram'),'~',
a.module,'~',a.message_txt,'~',a.time_stamp
FROM AW_ACTIVE_ALARMS a
LEFT JOIN AW_TRIGRAM_LOCATION b
ON b.site_id = a.site_id
AND b.zone_id = a.zone_id
WHERE a.zone_id = in_zone_id
AND a.module LIKE substr(in_mod,1,3)||'%'
AND weight = (select max(weight) from AW_ACTIVE_ALARMS c
WHERE c.site_id = in_site_id
AND c.zone_id = in_zone_id
AND c.module LIKE substr(in_mod,1,3)||'%');
You won't get NO_DATA_FOUND opening a cursor, only when you fetch from it (depending on what is actually consuming this). It's a bad idea to catch WHEN OTHERS anyway - you would want to catch WHEN NO_DATA_FOUND, though it wouldn't help here. And using dbms_output to report an error relies on the client enabling its display, which you can't generally assume.

Sorting by value returned by a function in oracle

I have a function that returns a value and displays a similarity between tracks, i want the returned result to be ordered by this returned value, but i cannot figure out a way on how to do it, here is what i have already tried:
CREATE OR REPLACE PROCEDURE proc_list_similar_tracks(frstTrack IN tracks.track_id%TYPE)
AS
sim number;
res tracks%rowtype;
chosenTrack tracks%rowtype;
BEGIN
select * into chosenTrack from tracks where track_id = frstTrack;
dbms_output.put_line('similarity between');
FOR res IN (select * from tracks WHERE ROWNUM <= 10)LOOP
SELECT * INTO sim FROM ( SELECT func_similarity(frstTrack, res.track_id)from dual order by sim) order by sim; //that's where i am getting the value and where i am trying to order
dbms_output.put_line( chosenTrack.track_name || '(' ||frstTrack|| ') and ' || res.track_name || '(' ||res.track_id|| ') ---->' || sim);
END LOOP;
END proc_list_similar_tracks;
/
declare
begin
proc_list_similar_tracks(437830);
end;
/
no errors are given, the list is just presented unsorted, is it not possible to order by a value that was returned by a function? if so, how do i accomplish something like this? or am i just doing something horribly wrong?
Any help will be appreciated
In the interests of (over-)optimisation I would avoid ordering by a function if I could possibly avoid it; especially one that queries other tables. If you're querying a table you should be able to add that part to your current query, which enables you to use it normally.
However, let's look at your function:
There's no point using DBMS_OUTPUT for anything but debugging unless you're going to be there looking at exactly what is output every time the function is run; you could remove these lines.
The following is used only for a DBMS_OUTPUT and is therefore an unnecessary SELECT and can be removed:
select * into chosenTrack from tracks where track_id = frstTrack;
You're selecting a random 10 rows from the table TRACKS; why?
FOR res IN (select * from tracks WHERE ROWNUM <= 10)LOOP
Your ORDER BY, order by sim, is ordering by a non-existent column as the column SIM hasn't been declared within the scope of the SELECT
Your ORDER BY is asking for the least similar as the default sort order is ascending (this may be correct but it seems wrong?)
Your function is not a function, it's a procedure (one without an OUT parameter).
Your SELECT INTO is attempting to place multiple rows into a single-row variable.
Assuming your "function" is altered to provide the maximum similarity between the parameter and a random 10 TRACK_IDs it might look as follows:
create or replace function list_similar_tracks (
frstTrack in tracks.track_id%type
) return number is
sim number;
begin
select max(func_similarity(frstTrack, track_id)) into sim
from tracks
where rownum <= 10
;
return sim;
end list_similar_tracks;
/
However, the name of the function seems to preclude that this is what you're actually attempting to do.
From your comments, your question is actually:
I have the following code; how do I print the top 10 function results? The current results are returned unsorted.
declare
sim number;
begin
for res in ( select * from tracks ) loop
select * into sim
from ( select func_similarity(var1, var2)
from dual
order by sim
)
order by sim;
end loop;
end;
/
The problem with the above is firstly that you're ordering by the variable sim, which is NULL in the first instance but changes thereafter. However, the select from DUAL is only a single row, which means you're randomly ordering by a single row. This brings us back to my point at the top - use SQL where possible.
In this case you can simply SELECT from the table TRACKS and order by the function result. To do this you need to give the column created by your function result an alias (or order by the positional argument as already described in Emmanuel's answer).
For instance:
select func_similarity(var1, var2) as function_result
from dual
Putting this together the code becomes:
begin
for res in ( select *
from ( select func_similarity(variable, track_id) as f
from tracks
order by f desc
)
where rownum <= 10 ) loop
-- do something
end loop;
end;
/
You have a query using a function, let's say something like:
select t.field1, t.field2, ..., function1(t.field1), ...
from table1 t
where ...
Oracle supports order by clause with column indexes, i.e. if the field returned by the function is the nth one in the select (here, field1 is in position 1, field2 in position 2), you just have to add:
order by n
For instance:
select t.field1, function1(t.field1) c2
from table1 t
where ...
order by 2 /* 2 being the index of the column computed by the function */

How to write the following pl/sql block without using Cursor?

I had written a cursor in a pl/sql block. This block taking lot of time if it has more records.
How to write this without a cursor or Is there any other alternative way that will reduce the time?
Is there any alternative query to perform insert into one table and delete from another table using a single query?
DECLARE
MDLCursor SYS_REFCURSOR;
BEGIN
open MDLCursor for
select dc.dest_id, dc.digits, dc.Effectivedate, dc.expirydate
from DialCodes dc
INNER JOIN MDL d
ON dc.Dest_ID = d.Dest_ID
AND d.PriceEntity = 1
join sysmdl_calltypes s
on s.call_type_id = v_CallType_ID
and s.dest_id = dc.Dest_ID
and s.call_type_id not in
(select calltype_id from ignore_calltype_for_routing)
order by length(dc.digits) desc, dc.digits desc;
loop
fetch MDLCursor
into v_mdldest_id, v_mdldigits, v_mdlEffectiveDate, v_mdlExpDate;
insert into tt_pendingcost_temp
(Dest_ID,
Digits,
CCASDigits,
Destination,
tariff_id,
NewCost,
Effectivedate,
ExpiryDate,
previous,
Currency)
select v_mdldest_id,
Digits,
v_mdldigits,
Destination,
tariff_id,
NewCost,
Effectivedate,
ExpiryDate,
previous,
Currency
FROM tt_PendingCost
where substr(Digits, 1, 2) = substr(v_MDLDigits, 1, 2)
and instr(Digits, v_MDLDigits) = 1
and v_mdlEffectiveDate <= effectivedate
and (v_mdlExpDate > effectivedate or v_mdlExpDate is null);
if SQL%ROWCOUNT > 0 then
delete FROM tt_PendingCost
where substr(Digits, 1, 2) = substr(v_MDLDigits, 1, 2)
and instr(Digits, v_MDLDigits) = 1
and v_mdlEffectiveDate <= effectivedate
and (v_mdlExpDate > effectivedate or v_mdlExpDate is null);
end if;
exit when MDLCursor%NOTFOUND;
end loop;
close MDLCursor;
END;
I don't have your tables and your data so I can only guess at a couple of things that would be slowing you down.
Firstly, the query used in your cursor has an ORDER BY clause in it. If this query returns a lot of rows, Oracle has to fetch them all and sort them all before it can return the first row. If this query typically returns a lot of results, and you don't particularly need it to return sorted results, you may find your PL/SQL block speeds up a bit if you drop the ORDER BY. That way, you can start getting results out of the cursor without needing to fetch all the results, store them somewhere and sort them first.
Secondly, the following is the WHERE clause used in your INSERT INTO ... SELECT ... and DELETE FROM ... statements:
where substr(Digits, 1, 2) = substr(v_MDLDigits, 1, 2)
and instr(Digits, v_MDLDigits) = 1
and v_mdlEffectiveDate <= effectivedate
and (v_mdlExpDate > effectivedate or v_mdlExpDate is null);
I don't see how Oracle can make effective use of indexes with any of these conditions. It would therefore have to do a full table scan each time.
The last two conditions seem reasonable and there doesn't seem a lot that can be done with them. I'd like to focus on the first two conditions as I think there's more scope for improvement with them.
The second of the four conditions is
instr(Digits, v_MDLDigits) = 1
This condition holds if and only if Digits starts with the contents of v_MDLDigits. A better way of writing this would be
Digits LIKE v_MDLDigits || '%'
The advantage of using LIKE in this situation instead of INSTR is that Oracle can make use of indexes when using LIKE. If you have an index on the Digits column, Oracle will be able to use it with this query. Oracle would then be able to focus in on those rows that start with the digits in v_MDLDigits instead of doing a full table scan.
The first of the four conditions is:
substr(Digits, 1, 2) = substr(v_MDLDigits, 1, 2)
If v_MDLDigits has length at least 2, and all entries in the Digits columns also have length at least 2, then this condition is redundant since it is implied by the previous one we looked at.
I'm not sure why you would have a condition like this. The only reason I can think why you might have this condition is if you have a functional index on substr(Digits, 1, 2). If not, I would be tempted to remove this substr condition altogether.
I don't think the cursor is what is making this procedure run slowly, and there's no single statement I know of that can insert into one table and delete from another. To make this procedure speed up I think you just need to tune the queries a bit.

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