INSERT Trigger to check for existing records

[Hagen Finley]

Hello,

I am definitely out over my skis here so I’ll apologize in advance 😉. 
Running version 12.5-1.pgdg20.04+1 on ubuntu. It’s essentially a 
personal database I use to ingest sales forecast spreadsheets from which 
I  create custom reports for my job function.


I pull a new forecast spreadsheet each Monday. 80% of the records are 
the same as the existing records from the week before.


Here’s what I (REALLY) want:

Trigger looks at three fields prior to new insert: Deal ID (numeric), 
revenue (numeric), stage(char)     Example: 19743576 22072.37    Commit 
- 90%


1. If the NEW dealid doesn't match any of the OLD dealids, insert the
   new row
2. if the NEW dealid, revenue and stage fields ALL match the OLD
   dealid, revenue and stage, skip (don't insert the NEW row)
3. If the NEW dealid matches an OLD dealid but either the NEW revenue
   OR the stage fields have changed (don't match OLD record) insert new
   row (I'll review both rows manually)


*Attempt 1: *Update chk field with 'same' if OLD revusd OR stage are 
different than the NEW revusd OR stage


CREATE TRIGGER chk4chg
BEFORE
    INSERT ON sfdc
    FOR EACH ROW
BEGIN
    UPDATE sfdc
    SET chk = 'same'
    WHERE ndealid = :NEW.ndealid
  AND revusd = :NEW.revusd
  AND stage = :NEW.stage
END chk4chg;

Remarkably, that works in that it will UPDATE the chk field with 'same'


|ndealid |revusd |stage |chk   |

|17713063|130|Propose - 60% |same  |

However, I must manually enter the parameters in dialogue box that 
(inexplicably) pops up when I run this command.



*Attempt 2:*

CREATE OR REPLACE FUNCTION update_insert() RETURNS trigger AS $$
BEGIN
    UPDATE sfdc
    SET chk = 'same'
    WHERE ndealid = OLD.ndealid;
    AND NEW.revusd = OLD.revusd
    AND NEW.stage = OLD.stage;
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

CREATE FUNCTION Query returned successfully in 136 msec.

That's good news but the trigger doesn't actually update. It lacks 
BEFORE INSERT ON sfdc FOR EACH ROW so low prospect for success :-).



*Attempt 3: *A little more sophisticated executing Function from Trigger

CREATE TRIGGER smart_update_same BEFORE INSERT ON sfdc
FOR EACH ROW EXECUTE FUNCTION update_insert();

CREATE OR REPLACE FUNCTION update_insert() RETURNS trigger AS $$
BEGIN
    UPDATE sfdc
    SET sfdc.chk = 'same'
    WHERE NEW.ndealid = OLD.ndealid
  AND NEW.revusd = OLD.revusd
  AND NEW.stage = OLD.stage;
END;
$$ LANGUAGE plpgsql;

These 2 CREATEs return successfully but do not update the chk field on a 
successful INSERT:


sales=# select ndealid,revusd,stage,chk from sfdc where ndealid = 19743576;

  ndealid   |  revusd  | stage  | chk

 19743576 | 22072.37 | Commit - 90%   |
   19743576 | 22072.37 | Commit - 90%   |
   19743576 | 22072.37 | Commit - 90%   |

These 3 attempts won't give me what I REALLY want but I figure I could 
use the chk field to delete the new inserts I didn't need.


Am I anywhere close (same county) to the right code?

Hagen

Larimer County, CO

Re: INSERT Trigger to check for existing records

[Hagen Finley]

Thanks so much Adrian,

I like this approach but as you indicated it doesn't actually NULL the 
INSERT.


Could we UPDATE the existing record (per my fledgling chk UPDATE and 
then RETURN NULL? (More proof I don't know what I am talking about ;-).


Hagen


On 11/21/20 10:11 AM, Adrian Klaver wrote:

On 11/21/20 8:47 AM, Adrian Klaver wrote:

On 11/21/20 8:20 AM, Adrian Klaver wrote:

On 11/21/20 8:00 AM, Hagen Finley wrote:

Hello,




Instead:

IF NEW.ndealid = OLD.ndealid AND NEW.revusd = OLD.revusd
 AND NEW.stage = OLD.stage THEN
 RETURN NULL; --Will cancel INSERT
ELSE
 RETURN NEW;

END IF;


Well this is what happens when I answer BC(before coffee). The above 
will not work, if for no other reason then OLD does not exist in an 
INSERT. Will try to come up with something that is in the realm of 
possibility.


Alright caffeine in the blood stream, so something that might actually 
work:


DECLARE
    match_ct integer;
BEGIN

    SELECT INTO
match_ct count(*)
    FROM
    sfdc
    WHERE
    ndealid = NEW.ndealid
    AND
    revusd = NEW.revusd
    AND
   stage = NEW.stage;

   IF match_ct > 0 THEN
   RETURN NULL; --Will cancel INSERT
   ELSE
   RETURN NEW;
   END IF;

END;

Though I would also point you at David's solution. Given that you are 
only looking at ~20% of the records being different it would save you 
a lot of churning through INSERTs.








Hagen

Larimer County, CO

Re: INSERT Trigger to check for existing records

[Hagen Finley]

David,

That's an interesting idea. I WOULD like  to retain the OLD records that 
are the same and only INSERT new or changed records. Is there a way to 
compare the old and the new records without a trigger?


Hagen

On 11/21/20 9:15 AM, David G. Johnston wrote:



On Saturday, November 21, 2020, Hagen Finley <mailto:ha...@datasundae.com>> wrote:



I pull a new forecast spreadsheet each Monday. 80% of the records
are the same as the existing records from the week before.

Here’s what I (REALLY) want:

Trigger looks at three fields prior to new insert: Deal ID
(numeric), revenue (numeric), stage(char)     Example: 19743576   
22072.37    Commit - 90%

 1. If the NEW dealid doesn't match any of the OLD dealids, insert
the new row
 2. if the NEW dealid, revenue and stage fields ALL match the OLD
dealid, revenue and stage, skip (don't insert the NEW row)
 3. If the NEW dealid matches an OLD dealid but either the NEW
revenue OR the stage fields have changed (don't match OLD
record) insert new row (I'll review both rows manually)


Am I anywhere close (same county) to the right code?



IMO, don’t use triggers.  Load the data into a temporary, or unlogged 
table, and then run commands to do what you want against the live 
tables.  Truncate/drop before doing that again the following week.


David J.

Re: INSERT Trigger to check for existing records

[Hagen Finley]

Hello Michael,

Thanks so much for this advice. As I mentioned previously, I'm not very 
good at this yet, so forgive me if my response is obtuse. I really love 
databases but my sentiments may be unrequited.


In reality my table has lots of columns (~30) including a report date 
(repdate) and each week's pull has a new repdate ( in this case 
2020-11-02 and 2020-11-09) which could function as a "created on" field.


To clarify, I would create an unique index on all the columns in the old 
report records (2020-11-02)  or just the three I am comparing 
(dealid,stage and revenue)?


In either case, so far in my efforts it looks like the create index 
fails because there are lots of rows with the same stage value, and a 
few with the same revenue value.


Create UNIQUE INDEX idx_sfdc
ON sfdc(ndealid, stage, revusd);

ERROR: could not create unique index "idx_sfdc" DETAIL: Key (ndealid, 
stage, revusd)=(19743576, Commit - 90% , 22072.37) is duplicated. SQL 
state: 23505


I probably could create an unique index on the dealid column as that 
should be unique. Would that be enough? It seems like that would insert 
ONLY the new records with a new (unique) dealid and that would 
definitely by an important step forward.


I hesitate to admit I have no idea how I would code the "call insert on 
conflict (unique index) do nothing" syntax, but I would be excited to learn.


Best,

Hagen


On 11/22/20 8:54 AM, Michael Lewis wrote:
If you can modify your insert statement, and live with an extra column 
in the data, no trigger is needed as best I can figure.


Create a unique index over the existing columns, add a "created_on" 
field and call insert on conflict (unique index) do nothing.


This should give the behavior you want.

Re: INSERT Trigger to check for existing records

[Hagen Finley]

Adrian and Michael,

My current insert logic (which works) is in a psycopg2 python script 
which reads a spreadsheet row into an array, so for the moment I didn't 
want to add that integration to my struggle.


   cur = conn.cursor()
   \
   query = "INSERT INTO
   
sfdc(theater,country,account,smotion,opname,cprod,opid,*ndealid,*qnum,*stage,revusd*,cdate,bdate,age,opown,opnum,sonum,fbdate,region,dqnum,pid,closed,won,onum,repdate)

   VALUES
   
(%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s);"

   cur.executemany(query, frecords)
   conn.commit()
   conn.close()


However, the following is something of a stepping stone towards the 
destination and, (dare I say it? ;-) it works:


CREATE OR REPLACE FUNCTION same_test(did numeric)
RETURNS numeric AS $$
BEGIN
  IF $1 IN
      (SELECT ndealid from hygiene_112)
  THEN
    UPDATE hygiene_119 SET paid = 'SAME';
  ELSE
      UPDATE hygiene_119 SET paid = 'NEW';
  END IF;
RETURN NULL;
END;
$$ LANGUAGE plpgsql;


I changed the dealid to something that doesn't exist (14593030) in the 
11-2 table and the function updates the 11-9 table.status field to "NEW":


sales=# UPDATE hygiene_112 SET ndealid = 14593030 WHERE ndealid = 14593039;
UPDATE 1

SELECT same_test(14593039);

+--+---+--++--+--+--+
|repdate   |ndealid |revusd    |stage |status  |
+--+---+--++--+--+--+
|2020-11-09|14593039|1015624.23|Propose - 60% *|NEW * |
+--+---+--++--+--+--+

When I changed it back I get the proper "SAME" update:

sales=# UPDATE hygiene_112 SET ndealid = 14593039 WHERE ndealid = 14593030;
UPDATE 1

SELECT same_test(14593039);

+--+---+--++--+--+--+
|repdate   |ndealid |revusd    |stage |status  |
+--+---+--++--+--+--+
|2020-11-09|14593039|1015624.23|Propose - 60% |*SAME * |
+--+---+--++--+--+--+


I'm generally amazed when ANYTHING works so this is good news (to me). 
It seems logical I could replace the UPDATE statement with an INSERT 
statement at this point.


However, that only addresses one of the /data rules /on my checklist.

I'll keep forging ahead here and see what additional progress I can 
attain. Very much appreciate your patient assistance here.


Best,

Hagen


On 11/22/20 11:26 AM, Adrian Klaver wrote:

On 11/22/20 9:53 AM, Hagen Finley wrote:

Hello Michael,

Thanks so much for this advice. As I mentioned previously, I'm not 
very good at this yet, so forgive me if my response is obtuse. I 
really love databases but my sentiments may be unrequited.


The overriding issue is lack of a plan. From your first post:

"Here’s what I (REALLY) want:


Trigger looks at three fields prior to new insert: Deal ID (numeric),
revenue (numeric), stage(char) Example: 19743576 22072.37 Commit
- 90%


 1. If the NEW dealid doesn't match any of the OLD dealids, insert the
    new row
 2. if the NEW dealid, revenue and stage fields ALL match the OLD
    dealid, revenue and stage, skip (don't insert the NEW row)
 3. If the NEW dealid matches an OLD dealid but either the NEW revenue
    OR the stage fields have changed (don't match OLD record) insert new
    row (I'll review both rows manually)
"

And from later post:

" I figure I could
use the chk field to delete the new inserts I didn't need."


From this I come up with the following:

1) Data rules

  a) If dealid in new data does not exist in old data INSERT row.
  b) Id dealid is in both new and old data AND revenue OR stage don't 
 match then INSERT and mark for review.
  c) If new dealid, revenue, stage match old dealid, revenue, stage 
then do not INSERT.


2) Process the data. Choices
   a) Use trigger on table sfdc
   b) Use staging table to hold new data and then process into sfdc table

3) Process the data. Same basic principle for both choices in 2) 
Flowchart
   a) In new data search for dealid in table sfdc if it does not exist 
add data to sfdc.

   b) If new data dealid does exist in sfdc
1) If revenue or stage field differ mark for review
2) If they do match skip further processing
4) Thoughts about above.

Re: INSERT Trigger to check for existing records : Does this do what I hope it is doing?

[Hagen Finley]

Folks,

Just a quick question. *Using this FUNCTION:*

   CREATE OR REPLACE FUNCTION same_test(did numeric)
   RETURNS numeric AS $$
   BEGIN
  IF $1 IN
      (SELECT dealid from hygiene_112)
  THEN
    UPDATE hygiene_119 SET paid = 'SAME';
  ELSE
      UPDATE hygiene_119 SET paid = 'NEW';
  END IF;
   RETURN NULL;
   END;
   $$ LANGUAGE plpgsql;

*Does the following query input the the dealids that result from the 
SELECT statement into the parameter of the sames_test() FUNCTION?*


Select dealid sametest(dealid) FROM hygiene_123;

I doubt it does (my query runs a /long time)/ :-). I know I can utilize 
python to push SELECT results into a array and then run a 'FOR d in 
dealids' LOOP to feed the FUNCTION parameter but I'd like to learn how 
to do that with nested SQL statements or FUNCTIONS.


Thanks!


Hagen


On 11/22/20 4:28 PM, Hagen Finley wrote:


Adrian and Michael,

My current insert logic (which works) is in a psycopg2 python script 
which reads a spreadsheet row into an array, so for the moment I 
didn't want to add that integration to my struggle.


cur = conn.cursor()
\
query = "INSERT INTO

sfdc(theater,country,account,smotion,opname,cprod,opid,*ndealid,*qnum,*stage,revusd*,cdate,bdate,age,opown,opnum,sonum,fbdate,region,dqnum,pid,closed,won,onum,repdate)

VALUES

(%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s,%s);"

cur.executemany(query, frecords)
conn.commit()
conn.close()


However, the following is something of a stepping stone towards the 
destination and, (dare I say it? ;-) it works:


CREATE OR REPLACE FUNCTION same_test(did numeric)
RETURNS numeric AS $$
BEGIN
  IF $1 IN
      (SELECT ndealid from hygiene_112)
  THEN
    UPDATE hygiene_119 SET paid = 'SAME';
  ELSE
      UPDATE hygiene_119 SET paid = 'NEW';
  END IF;
RETURN NULL;
END;
$$ LANGUAGE plpgsql;


I changed the dealid to something that doesn't exist (14593030) in the 
11-2 table and the function updates the 11-9 table.status field to "NEW":


sales=# UPDATE hygiene_112 SET ndealid = 14593030 WHERE ndealid = 
14593039;

UPDATE 1

SELECT same_test(14593039);

+--+---+--++--+--+--+
|repdate   |ndealid |revusd    |stage |status  |
+--+---+--++--+--+--+
|2020-11-09|14593039|1015624.23|Propose - 60% *|NEW * |
+--+---+--++--+--+--+

When I changed it back I get the proper "SAME" update:

sales=# UPDATE hygiene_112 SET ndealid = 14593039 WHERE ndealid = 
14593030;

UPDATE 1

SELECT same_test(14593039);

+--+---+--++--+--+--+
|repdate   |ndealid |revusd    |stage |status  |
+--+---+--++--+--+--+
|2020-11-09|14593039|1015624.23|Propose - 60% |*SAME * |
+--+---+--++--+--+--+


I'm generally amazed when ANYTHING works so this is good news (to me). 
It seems logical I could replace the UPDATE statement with an INSERT 
statement at this point.


However, that only addresses one of the /data rules /on my checklist.

I'll keep forging ahead here and see what additional progress I can 
attain. Very much appreciate your patient assistance here.


Best,

Hagen


On 11/22/20 11:26 AM, Adrian Klaver wrote:

On 11/22/20 9:53 AM, Hagen Finley wrote:

Hello Michael,

Thanks so much for this advice. As I mentioned previously, I'm not 
very good at this yet, so forgive me if my response is obtuse. I 
really love databases but my sentiments may be unrequited.


The overriding issue is lack of a plan. From your first post:

"Here’s what I (REALLY) want:


Trigger looks at three fields prior to new insert: Deal ID (numeric),
revenue (numeric), stage(char) Example: 19743576 22072.37 Commit
- 90%


 1. If the NEW dealid doesn't match any of the OLD dealids, insert the
    new row
 2. if the NEW dealid, revenue and stage fields ALL match the OLD
    dealid, revenue and stage, skip (don't insert the NEW row)
 3. If the NEW dealid matches an OLD dealid but either the NEW revenue
    OR the stage fields have changed (don't match OLD record) insert new
    row (I'll review bo