I have a table with multiple columns which consists of a composite primary key for three of them (columns customer_id,system_origin,policy_number).
The table is created as below :
Create table LOST_MEMBER_ACCESS_LOG (
Customer_id varchar2(20) NOT NULL,
System_Origin varchar2(20) NOT NULL,
Policy_Number varchar2(20) NOT_NULL,
PRIMARY_KEY(Customer_id,System_Origin, Policy_Number)
);
I have a requirement to write a stored proc which firsts checks if a row already exists for unique combination for customer_id,system_origin,policy_number then it updates the already existing row with the new values or else it inserts a new row.
What you're saying you want to do is:
if row exists then
update ...
else
insert ...
end if;
But there is easier way. Just do the update and check if any row was touched
update lost_member_access_log
set ...
where ... ;
if sql%rowcount = 0 then
insert into lost_member_access_log ...
end if;
MERGE is of course also an option.
Related
In an Oracle Database, I need to create some trigger or procedure to treat this case in the most performative way possible (is an extremely large amount of data).
I have a table called ORDER_A that every day receives a full load (its truncated, and all records are inserted again).
I have a table called ORDER_B which is a copy of ORDER_A, containing the same data and some additional control dates.
Each insertion on ORDER_A must trigger a process that looks for a record with the same identifier (primary key: order_id) in table B.
If a record exists with the same order_id, and any of the other columns have changed, an update must be performed on table B
If a record exists with the same order_id, and no values in the other columns have been modified, nothing should be performed, the record must remain the same in table B.
If there is no record with the same order_id, it must be inserted in table B.
My tables are like this
CREATE TABLE ORDER_A
(
ORDER_ID NUMBER NOT NULL,
ORDER_CODE VARCHAR2(50),
ORDER_STATUS VARCHAR2(20),
ORDER_USER_ID NUMBER,
ORDER_DATE TIMESTAMP(6),
PRIMARY KEY (ORDER_ID)
);
CREATE TABLE ORDER_B
(
ORDER_ID NUMBER NOT NULL,
ORDER_CODE VARCHAR2(50),
ORDER_STATUS VARCHAR2(20),
ORDER_USER_ID NUMBER,
ORDER_DATE TIMESTAMP(6)
INSERT_AT TIMESTAMP(6),
UPDATED_AT TIMESTAMP(6),
PRIMARY KEY (ORDER_ID)
);
I have no idea how to do this and what is the best way (with a trigger, procedure, using merge, etc.)
Can someone give me a direction, please?
Here is some pseudo-code to show you a potential trigger based solution that does not fall back into slow row-by-row processing.
create or replace trigger mytrg
for insert or update delete on ordera
compound trigger
pklist sys.odcinumberlist;
before statement is
begin
pklist := sys.odcinumberlist();
end before statement ;
after each row is
begin
pklist.extend;
pklist(pklist.count) := :new.order_id;
end before each row;
after statement is
begin
merge into orderb b
using (
select a.*
from ordera a,
table(pklist) t
where a.order_id = t.column_value
) m
when matched then
update
set b.order_code = m.order_code,
b.order_status = m.order_status,
...
where decode(b.order_code,m.order_code,0,1)=1
or decode(b.order_status,m.order_status,0,1)=1
....
when not matched then
insert (b.order_id,b.order_code,....)
values (m.order_id,m.order_code,....);
end after statement ;
end;
We hold the impacted primary keys, and then build a single merge later, with an WHERE embed to minimise update activities.
If your application allows the update of primary keys, you'd need some additions, but this should get you started
Basically, users when they create a new record in mytable1, there is an id field that needs to be the same across multiple tables. I achieve this by having mytable2 with the s_id as primary key
My current function looks like
CREATE OR REPLACE FUNCTION test.new_record()
RETURNS trigger
LANGUAGE plpgsql
AS $function$
BEGIN
case when new.s_id in (select s_id from mytable1) then
insert into mytable2 (sprn, date_created) select max(s_id) +1, now() from mytable2 ;
update mytable1 set new.s_id = (select max(b.s_id) from mytable2 b);
end case;
RETURN new;
END;
$function$;
Intended was when the s_id is replicated then it would create a new entry on mytable2. This new entry would then be updated onto mytable1
Problem with this function is that right now it does not recognise the new on the update part of the function.
How to keep the s_id take the value on every new insert ?
If you want to have one "generator" across multiple tables, create one sequence that is used across all those tables for the default value:
create sequence the_id_sequence;
create table one
(
id integer primary key default nextval('the_id_sequence')
.... other columns
);
create table two
(
id integer primary key default nextval('the_id_sequence')
.... other columns ...
);
If you want to replicate an ID from one table to another during insert, you only need one sequence:
create table one
(
-- using identity is the preferred over "serial" to auto-generate PK values
id integer primary key generated always as identity
);
create table two
(
id integer primary key
);
create or replace function insert_two()
returns trigger
as
$$
begin
insert into two (id) values (new.id);
return new;
end;
$$
language plpgsql;
create trigger replicate_id
before insert on one
for each row
execute procedure insert_two();
Then if you run:
insert into one (id) values (default);
A row with exactly the same id value will be inserted into table two.
If you don't have a generated ID column so far, use the following syntax:
alter table one
add testidcolumn bigint generated always as identity;
Looking for an ideal way to store (1) date & time of update (2) updater/user per row of table data using Oracle Apex. I am thinking of adding 2 extra columns to store the info and trying to come up with a good as to how changes per row can be tracked.
If you want create logs of insert, update , delete on your table, adding 2 columns not enough. Each new update will erase previous and delete couldn't be logged. So you need to store log table separately from data table, and fill it on before and after triggers created on your data table. If you want sample I can provide some.
Here simplified example, of course in real life data will be more complex and I guess a trigger should be more smarter, but this is a simple start point to create your own. After executing codes below, try to insert, update, delete delete records in table TEST_DATA, see what happens in TEST_LOG
Create data table
create table TEST_DATA (
UNID number,
COL_B varchar2(50)
);
-- Create/Recreate primary, unique and foreign key constraints
alter table TEST_DATA
add constraint PK_TEST_DATA_UNID primary key (UNID);
Create log table for it
create table TEST_LOG (
UNID number,
OPERATION varchar2(1),
COL_OLD varchar2(50),
COL_NEW varchar2(50),
CHNGUSER varchar2(50),
CHNGDATE date
);
and finally create trigger which tracks changes
create or replace trigger TR_LOG_TEST_DATA
after update or insert or delete on TEST_DATA
referencing new as new old as old
for each row
begin
if Inserting then
insert into TEST_LOG
(UNID, OPERATION, COL_OLD, COL_NEW, CHNGUSER, CHNGDATE)
values
(:new.unid, 'I', null, :new.col_b, user, sysdate);
end if;
if Updating then
insert into TEST_LOG
(UNID, OPERATION, COL_OLD, COL_NEW, CHNGUSER, CHNGDATE)
values
(:new.unid, 'U', :old.col_b, :new.col_b, user, sysdate);
end if;
if Deleting then
insert into TEST_LOG
(UNID, OPERATION, COL_OLD, COL_NEW, CHNGUSER, CHNGDATE)
values
(:old.unid, 'D', :old.col_b, null, user, sysdate);
end if;
end;
I defined a BEFORE INSERT trigger for a table and it works as expected for single INSERTstatements, but not for INSERT ... SELECT nor MERGE statements.
These are my database objects (simplified):
CREATE TABLE "COMPANY" (
"ID" NUMBER NOT NULL,
"NAME" VARCHAR(100)
);
CREATE TABLE "EMPLOYEE" (
"ID" NUMBER NOT NULL,
"COMPANY_ID" NUMBER NOT NULL
);
CREATE UNIQUE INDEX "EMPLOYEE_PK" ON "EMPLOYEE" ("ID");
CREATE SEQUENCE "EMPLOYEE_SEQUENCE";
CREATE TRIGGER "BI_EMPLOYEE" BEFORE INSERT ON "EMPLOYEE"
REFERENCING NEW AS newrow FOR EACH ROW BEGIN ATOMIC
IF newrow.id IS NULL THEN
SET newrow.id = NEXT VALUE FOR employee_sequence;
END IF;
END;
If single INSERTstatements are executed, everything works as expected, the ÌD is fetched from the sequence. But if I execute something like
INSERT INTO employee (company_id) SELECT id FROM company;
the I get an error:
integrity constraint violation: unique constraint or index violation: "EMPLOYEE_PK"
which could propably mean that it tries to insert the same key from the sequence twice.
I'm using the latests version 2.3.2 of HSQLDB.
Because triggers are set based, not row based.
See details here
we want to create a trigger which checks if a new measurement (=messung) point lies within the current glacier shape (=umriss).
are tables look like this:
glacier shape (=Umriss)
create table umriss
(
umr_nr number (4) not null,
umr_datum date,
GLST_ID number (4) not null,
shape mdsys.sdo_geometry,
GLETSCHER_ID number (3) not null
)
;
alter table umriss
add constraint umriss_glst_pk
primary key (umr_nr, GLST_ID, GLETSCHER_ID)
;
ALTER TABLE umriss
ADD CONSTRAINT umriss_gletscherstand_fk
FOREIGN KEY (GLST_ID, GLETSCHER_ID)
REFERENCES GLETSCHERSTAND(GLST_ID, GLETSCHER_ID);
new measurement (=Messung)
CREATE TABLE MESSUNG
(
MESS_NR number (4) not null,
MESS_DAT date,
MESS_AKK number (20) NOT NULL,
MESS_SCHMELZ number (20) NOT NULL,
SHAPE mdsys.sdo_geometry,
MESS_BILD blob,
KMPGN_NR NUMBER (4) NOT NULL
);
ALTER TABLE MESSUNG
ADD CONSTRAINT messung_pk
PRIMARY KEY (MESS_NR);
ALTER TABLE MESSUNG
ADD CONSTRAINT messung_messkampagne_fk
FOREIGN KEY (KMPGN_NR)
REFERENCES MESSKAMPAGNE(KMPGN_NR);
Trigger
CREATE OR REPLACE
TRIGGER MESSUNG_in_UMRISS_TRI
BEFORE INSERT OR UPDATE ON MESSUNG
FOR EACH ROW
DECLARE
num_check NUMBER;
BEGIN
SELECT COUNT (*) INTO num_check
FROM UMRISS u
WHERE mdsys.sdo_contains (u.shape, :NEW.point) = 'TRUE';
IF num_check <> 1
THEN
RAISE_APPLICATION_ERROR (=20500, 'Messung in keinem Umriss')
END IF;
END;
How do we iplement the function so the trigger only checks within the most curretn glacier shape?
Thanks for your help!
This will return the one row fron UMRISS which matches the most recent date in the table.
SELECT COUNT (*) INTO num_check
FROM UMRISS u
WHERE mdsys.sdo_contains (u.shape, :NEW.point) = 'TRUE'
AND u.umr_datum = ( select max(d.;umr_datum) from UMRISS d );
This sort of query is the price for keeping historical data in teh same table as the current record.
it seems that POINT ist not defined in your example?
However, you might consider a check constraint because a trigger would only be enforced when a MESSUNG record is inserted or updated, but not when UMRISS is changed
alter table MESSUNG add constraint MESSUNG_CC_CONTAINS check(mdsys.sdo_contains (shape, point) = 'TRUE')
In case you're frequently updating the UMRISS records it might not be feasable at all to enforce such a constraint because Oracle would have to check all MESSUNG records when UMRISS is updated or deleted. Perhaps consider an additional mapping table between MESSUNG and UMRISS that you can update separately.