Working on an Insert trigger. How can I check a field for a specific character (in this case, a dash between two airline codes) when creating an If statement within that trigger?
IF schema.table.field (**contains**?) '-' THEN
SET #origin = (SELECT SUBSTR(field,1,3) FROM table WHERE parameters
SET #delivery = (SELECT SUBSTR(field,5,3)
ELSE
END IF;
This is what I implemented. So far it seems to be working as intended.
IF LOCATE('-',(SELECT table.field FROM table
WHERE table.field2=triggeringtable.field3)) > 0 THEN
SET #dashcheck = 1;
END IF;
I'll adjust this if anything breaks. If anyone sees any flaws in this that I may have missed, please feel free to say so.
Related
I'm relatively new to triggers so forgive me if this doesn't look how it should. I am creating a trigger that checks a user account for last payment date and sets a value to 0 if they haven't paid in a while. I created what I thought was a correct trigger but I get the error, "error during execution of trigger" when its triggered. From what I understand the select statement is causing the error as it selecting values which are in the process of being changed. Here is my code.
CREATE OR REPLACE TRIGGER t
BEFORE
UPDATE OF LASTLOGINDATE
ON USERS
FOR EACH ROW
DECLARE
USER_CHECK NUMBER;
PAYMENTDATE_CHECK DATE;
ISACTIVE_CHECK CHAR(1);
BEGIN
SELECT U.USERID, U.ISACTIVE, UP.PAYMENTDATE
INTO USER_CHECK, PAYMENTDATE_CHECK, ISACTIVE_CHECK
FROM USERS U JOIN USERPAYMENTS UP ON U.USERID = UP.USERID
WHERE UP.PAYMENTDATE < TRUNC(SYSDATE-60);
IF ISACTIVE_CHECK = 1 THEN
UPDATE USERS U
SET ISACTIVE = 0
WHERE U.USERID = USER_CHECK;
INSERT INTO DEACTIVATEDUSERS
VALUES(USER_CHECK,SYSDATE);
END IF;
END;
From what I thought, since the select is in the begin statement, it would run before an update, nothing would be changing about the tables until after if runs through the trigger. I tried but using :old in front of the select variables but that doesn't seem to be the right use.
And here is the update statement i was trying.
UPDATE USERS
SET LASTLOGINDATE = SYSDATE
WHERE USERID = 5;
Some issues:
The select you do in the trigger sets the variable isactive_check to a payment date, and vice versa. There is an accidental switch there, which will have a negative effect on the next if;
The same select should return exactly one record, which by the looks of it is not guaranteed, since you join with table userpayments, which may have several payments for the selected user that meet the condition, or none at all. Change that select to do an aggregation.
If a user has more than one payment record, the condition might be true for one, but not for another. So if you are interested only in users who have not paid in a long while, such user should not be included, even though they have an old payment record. Instead you should check whether all records meet the condition. This you can do with a having clause.
As the table users is mutating (the update trigger is on that table), you cannot perform every action on that same table, as it would otherwise lead to a kind of deadlock. This means you need to rethink what the purpose is of the trigger. As this is about an update for a specific user, you actually don't need to check the whole table, but only the record that is being changed. For that you can use the special new variable.
I would suggest this SQL instead:
SELECT MAX(UP.PAYMENTDATE)
INTO PAYMENTDATE_CHECK
FROM USERPAYMENTS
WHERE USERID = :NEW.USERID
and then continue with the checks:
IF :NEW.ISACTIVE = 1 AND PAYMENTDATE_CHECK < TRUNC(SYSDATE-60) THEN
:NEW.ISACTIVE := 0;
INSERT INTO DEACTIVATEDUSERS (USER_ID, DEACTIVATION_DATE)
VALUES(USER_CHECK,SYSDATE);
END IF;
Now you have avoided to do anything in the table users and have made the checks and modification via the :new "record".
Also, it is good practice to mention the column names in an insert statement, which I have done in above code (adapt column names as needed):
Make sure the trigger is compiled and produces no compilation errors.
I have a table with common word values to match against brands - so when someone types in "coke" I want to match any possible brand names associated with it as well as the original term.
CREATE TABLE word_association ( commonterm TEXT, assocterm TEXT);
INSERT INTO word_association ('coke', 'coca-cola'), ('coke', 'cocacola'), ('coke', 'coca-cola');
I have a function to create a list of these values in a pipe-delim string for pattern matching:
CREATE OR REPLACE FUNCTION usp_get_search_terms(userterm text)
RETURNS text AS
$BODY$DECLARE
returnstr TEXT DEFAULT '';
BEGIN
SET DATESTYLE TO DMY;
returnstr := userterm;
IF EXISTS (SELECT 1 FROM word_association WHERE LOWER(commonterm) = LOWER(userterm)) THEN
SELECT returnstr || '|' || string_agg(assocterm, '|') INTO returnstr
FROM word_association
WHERE commonterm = userterm;
END IF;
RETURN returnstr;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION usp_get_search_terms(text)
OWNER TO customer_role;
If you call SELECT * FROM usp_get_search_terms('coke') you end up with
coke|coca-cola|cocacola|coca cola
EDIT: this function runs <100ms so it works fine.
I want to run a query with this text inserted e.g.
SELECT X.article_number, X.online_description
FROM articles X
WHERE LOWER(X.online_description) % usp_get_search_terms ('coke');
This takes approx 56s to run against my table of ~500K records.
If I get the raw text and use it in the query it takes ~300ms e.g.
SELECT X.article_number, X.online_description
FROM articles X
WHERE X.online_description % '(coke|coca-cola|cocacola|coca cola)';
The result sets are identical.
I've tried modifying what the output string from the function to e.g. enclose it in quotes and parentheses but it doesn't seem to make a difference.
Can someone please advise why there is a difference here? Is it the data type or something about calling functions inside queries? Thanks.
Your function might take 100ms, but it's not calling your function once; it's calling it 500,000 times.
It's because your function is declared VOLATILE. This tells Postgres that either the function returns different values when called multiple times within a query (like clock_timestamp() or random()), or that it alters the state of the database in some way (for example, by inserting records).
If your function contains only SELECTs, with no INSERTs, calls to other VOLATILE functions, or other side-effects, then you can declare it STABLE instead. This tells the planner that it can call the function just once and reuse the result without affecting the outcome of the query.
But your function does have side-effects, due to the SET DATESTYLE statement, which takes effect for the rest of the session. I doubt this was the intention, however. You may be able to remove it, as it doesn't look like date formatting is relevant to anything in there. But if it is necessary, the correct approach is to use the SET clause of the CREATE FUNCTION statement to change it only for the duration of the function call:
...
$BODY$
LANGUAGE plpgsql STABLE
SET DATESTYLE TO DMY
COST 100;
The other issue with the slow version of the query is the call to LOWER(X.online_description), which will prevent the query from utilising the index (since online_description is indexed, but LOWER(online_description) is not).
With these changes, the performance of both queries is the same; see this SQLFiddle.
So the answer came to me about dawn this morning - CTEs to the rescue!
Particularly as this is the "simple" version of a very large query, it helps to get this defined once in isolation, then do the matching against it. The alternative (given I'm calling this from a NodeJS platform) is to have one request retrieve the string of terms, then make another request to pass the string back. Not elegant.
WITH matches AS
( SELECT * FROM usp_get_search_terms('coke') )
, main AS
( SELECT X.article_number, X.online_description
FROM articles X
JOIN matches M ON X.online_description % M.usp_get_search_terms )
SELECT * FROM main
Execution time is somewhere around 300-500ms depending on term searched and articles returned.
Thanks for all your input guys - I've learned a few things about PostGres that my MS-SQL background didn't necessarily prepare me for :)
Have you tried removing the IF EXISTS() and simply using:
SELECT returnstr || '|' || string_agg(assocterm, '|') INTO returnstr
FROM word_association
WHERE LOWER(commonterm) = LOWER(userterm)
In instead of calling the function for each row call it once:
select x.article_number, x.online_description
from
woolworths.articles x
cross join
woolworths.usp_get_search_terms ('coke') c (s)
where lower(x.online_description) % s
This is a SQL learning exercise. I have a 'tbl' with a single integer field. There are no indices on this table. I have this function:
CREATE OR REPLACE FUNCTION rcs()
RETURNS VOID AS $$
DECLARE
c CURSOR FOR SELECT * FROM tbl ORDER BY sequence;
s INTEGER;
r RECORD;
BEGIN
s := 0;
OPEN c;
LOOP
FETCH c INTO r;
EXIT WHEN NOT FOUND;
RAISE NOTICE 'got it';
r.sequence = s;
s := s + 1;
RAISE NOTICE '%', r.sequence;
END LOOP;
CLOSE c;
END;
$$ language 'plpgsql'
This loads and runs cleanly and the RAISE statements suggest that the 'sequence' field gets updated to 0, 1 etc. in accordance with the ORDER BY.
However, when I SELECT the table afterwards, the pre-existing values (which happen to all be '6') did not change.
Is this something to do with transactions? I tried fiddling around with COMMIT, etc. to no avail.
This is a freshly installed Postgresql 9.4.4 running on a Linode with no hackery of config files or anything like that, from the 'psql' command line.
EDIT: maybe it's because 'r' isn't actually the DB table, it's some kind of temporary copy of it? If so, please clarify, hopefully what I'm trying to achieve here is obvious (and I know it may be a bit nonsensical, but surely it's possible without resorting to reading the set into Java, etc.)
The actual problem: your function does not contain an UPDATE statement so nothing gets written to disk. r.sequence = s; simply assigns a new value to a variable that is held in memory.
To fix this, you need something like:
UPDATE tbl
set sequence = s -- change the actual column in the table
WHERE current of c; -- for the current row of your cursor
If where current of doesn't work, you need to switch that to a "regular" where clause:
UPDATE tbl
set sequence = s
WHERE tbl.pk_column = r.pk_column; -- the current primary key value
But a much more efficient solution is to do this in a single statement:
update tbl
set sequence = tu.new_sequence
from (
select t.pk_column,
row_number() over (order by t.sequence) as new_sequence
from tbl t
) tu
where tbl.pk_column = tu.pk_column;
You need to replace the column name pk_column with the real primary key (or unique) column of your table.
I have two columns and i need to copy of data from column VISITSAUTHORIZED to NEWVISITS, When i use below command to copy data i am getting an error message "invalid number".Can anyone correct this ?
VISITSAUTHORIZED VARCHAR2(10)
NEWVISITS NUMBER(8)
SQL> update patientinsurance set NEWVISITS=VISITSAUTHORIZED ;
ERROR at line 1:
ORA-01722: invalid number
It depends what kind of data you have in your old column. If it is all consistently formatted then you might be able to do:
update patientinsurance
set newvisits = to_number(visitsauthorized, '<format model>')
But it sounds more likely that you have something less easy to deal with. (The joys of storing data as the wrong datatype, which I assume is what you're now correcting). If there are rogue characters then you could use translate to get rid of them, perhaps, but you'd have to wonder about the integrity of the data and the values you end up with.
You can do something like this to display all the values that can't be converted, which may give you an idea of the best way to proceed - if there are only a few you might be able to correct them manually before re-running your update:
set serveroutput on
declare
newvisits number;
number_format_exception exception;
pragma exception_init(number_format_exception, -6502);
begin
for r in (select id, visitsauthorized from patientinsurance) loop
begin
newvisits := to_number(r.visitsauthorized);
exception
when number_format_exception then
dbms_output.put_line(sqlcode || ' ID ' || r.id
|| ' value ' || r.visitsauthorized);
end;
end loop;
end;
/
This is guessing you have a unique identifier field called ID, but change that as appropriate for your table, obviously.
Another approach is to convert the numbers that are valid and skip over the rest, which you can do with an error logging table:
exec dbms_errlog.create_error_log(dml_table_name => 'PATIENTINSURANCE');
merge into patientinsurance target
using (select id, visitsauthorized from patientinsurance) source
on (target.id = source.id)
when matched then
update set target.newvisits = source.visitsauthorized
log errors into err$_patientinsurance reject limit unlimited;
You can then query the error table to see what failed:
select id, visitsauthorized, ora_err_number$
from err$_patientinsurance;
Or see which records in your main table have newvisits still null. Analysing your data should probably be the first step though.
If you want to strip out all non-numeric characters and treat whatever is left as a number then you can change the merge to do:
...
update set target.newvisits = regexp_replace(source.visitsauthorized,
'[^[:digit:]]', null)
But then you probably don't need the merge, you can just do:
update patientinsurance set newvisits = regexp_replace(visitsauthorized,
'[^[:digit:]]', null);
This will strip out any group or decimal separators as well, which might not be an issue, particularly as you're inserting into a number(8) column. But you could preserve those if you wanted to, by changing the pattern to '[^[:digit:].,]'... though that could give you other problems still, potentially.
You can also do this with translate if the regex is too slow.
this is my code:
create or replace trigger th
after insert on stock
for each row
declare
sqty number;
rl number;
isb number;
rq number;
begin
set sqty=(select stockqty from inserted);
set rl=(select reorderlevel from inserted);
set isb=(select isbn from inserted);
set rq=(select reorderquantity from inserted);
go
if sqty> rl then
delete from stock where isb=isbn;
insert into stock values(isb,sqty,rl,rq);
end if;
end;
questions:
1.if a after insert trigger is used it means all this happens after inserting right?what if i want to not insert a particular data what do i do?i mean like if weight<15 dont insert like that.
2.if i have inserted multiple data how to retrieve them?does a trigger get called for each of the insert?(if its an insert trigger).
3.this is giving me a compilation error,i just am not able to find the mistake,even using a cursor is giving me an error.
create or replace trigger t1
after insert on stock for each row
declare
cursor cl is select isbn,stockqty,reorderlevel,reorderquantity from stock where isbn>0;
begin
for c2 in c1 loop
if c2.stockqty>c2.reorderlevel then
delete from stock where isbn=c2.isbn;
insert into stock values(c2.isbn,c2.reorderquantity,c2.reorderlevel,c2.reorderquantity);
end if;
end loop;
end;
Btw i am using sql developer,weidly many of my trigger are not executing,but they are executing in oracle 8i.
I can't figure out what you are trying to do, but your syntax is all wrong (where did you get it from? SQL Server?). See documentation for the correct syntax.
You wrote:
set sqty=(select stockqty from inserted);
I suspect you want to do this:
sqty := :new.stockqty;
Ditto the next 3 lines.
Then you have:
go
which is nonsense. Just remove it.
Then you have:
if sqty> rl then
delete from stock where isb=isbn;
insert into stock values(isb,sqty,rl,rq);
end if;
Which appears to mean that if the inserted row's stockqty exceeds its reorderlevel then delete it and then insert it right back in again. This makes no sense, and cannot be done using a FOR EACH ROW trigger as you will get the "table is mutating" error.
Please explain what you are trying to achieve and then we can help see if it can be achieved.
Answers:
1. You can use a Check Constraint for that
2. I don't understand what you mean:
if you want to find duplicated records then you can group by all fields and use
having count(*) >0
but why use a trigger ?
or maybe you mean that you want the values within the trigger ? if so, use
:new and :old