I have a trigger like this: (Basically on update of a column in table1, I update a column in table 2)
CREATE OR REPLACE TRIGGER AAA AFTER UPDATE
ON TABLE_1 REFERENCING NEW AS NEWROW OLD AS OLDROW
FOR EACH ROW
WHEN (
NEWROW.DELETED ='Y' AND NEWROW.ID IN (41,43)
AND OLDROW.DELETED = 'N'
)
DECLARE
id_1 number;
id_2 number;
id_3 number;
BEGIN
select id_1, id_2,id_3 into id_1,id_2,id_3 from table_1 where id_1 = :NEWROW.id1 and id2 = some_other_row.id2;
if id_1 is null
then
update table2 set deleted = 'Y' , where table2.id_1 = id_1 and table2.id_2=id_2 and table2.id_3 = id_3;
end if;
EXCEPTION
WHEN OTHERS
THEN
-- Consider logging the error and then re-raise
RAISE;
END AAA;
/
When I update table1 I get:
ORA-04091: table table1 is mutating, trigger/function may not see it
I thought this error happens only when you are updating the table on which the trigger is trying to update something. But here I am updating table1 and trigger is supposed to update table2. SO why is the error?
It's the SELECT statement that is causing the problem here. Inside the trigger, you cannot SELECT from the same table. In your example, you don't need/can't use the SELECT statement. You can get the values by simply using :newrow.id_1, :newrow.id_2 and :newrow.id_3.
Related
the issue:
i need to do something like this
drop table if exists tt_t;
create temp table tt_t(id serial primary key, main_id int, external_id int);
insert into tt_t(main_id, external_id)
select currval(pg_get_serial_sequence('tt_t', 'id')), 1
where not exists (select from tt_t where external_id = 1);
but execution raises an error
SQL Error [55000]: ERROR: currval of sequence "tt_t_id_seq" is not yet defined in this session
solution:
there is a way to solve this with anonymous code block
do
$$
begin
if not exists(select from tt_t where external_id = 1)
then
insert into tt_t(external_id, main_id)
values(1, currval(pg_get_serial_sequence('tt_t', 'id')));
end if;
end;
$$
;
but anonymous blocks has some restrictions e.g. Dapper parameters not working with PostgreSQL through npgsql connection, is postgres anonymous function parameterization supported?
how do i fix it without anonymous code block (UPD: and without any DDL changes)?
probable solution:
insert into tt_t(id, main_id, external_id)
select nextval(pg_get_serial_sequence('tt_t', 'id')), currval(pg_get_serial_sequence('tt_t', 'id')), 1
where not exists (select from tt_t where external_id = 1);
shorter code has been proposed to me
insert into tt_t(id, main_id, external_id)
select nextval(pg_get_serial_sequence('tt_t', 'id')), lastval(), 1
where not exists (select from tt_t where external_id = 1);
but i'm not sure if nextval will be calculated first
What about using a default value:
drop table if exists tt_t;
create temp table tt_t(id serial primary key, main_id int default lastval(), external_id int);
insert into tt_t(external_id)
select 1
where not exists (select * from tt_t where external_id = 1);
In theory it shouldn't be possible that another nextval() is called between the one for the id and the lastval(). However I am not 100% sure if there are some corner cases that I don't know of.
The following works as well (even if one or more of the external_id values already exist).
insert into tt_t(external_id)
select *
from (values (1),(2),(3)) x (external_id)
where not exists (select *
from tt_t
where external_id = x.external_id);
I am writing migration script to migrate database. I have to duplicate the row by incrementing primary key considering that different database can have n number of different columns in the table. I can't write each and every column in query. If i simply just copy the row then, I am getting duplicate key error.
Query: INSERT INTO table_name SELECT * FROM table_name WHERE id=255;
ERROR: duplicate key value violates unique constraint "table_name_pkey"
DETAIL: Key (id)=(255) already exist
Here, It's good that I don't have to mention all column names. I can select all columns by giving *. But, same time I am also getting duplicate key error.
What's the solution of this problem? Any help would be appreciated. Thanks in advance.
If you are willing to type all column names, you may write
INSERT INTO table_name (
pri_key
,col2
,col3
)
SELECT (
SELECT MAX(pri_key) + 1
FROM table_name
)
,col2
,col3
FROM table_name
WHERE id = 255;
Other option (without typing all columns , but you know the primary key ) is to CREATE a temp table, update it and re-insert within a transaction.
BEGIN;
CREATE TEMP TABLE temp_tab ON COMMIT DROP AS SELECT * FROM table_name WHERE id=255;
UPDATE temp_tab SET pri_key_col = ( select MAX(pri_key_col) + 1 FROM table_name );
INSERT INTO table_name select * FROM temp_tab;
COMMIT;
This is just a DO block but you could create a function that takes things like the table name etc as parameters.
Setup:
CREATE TABLE public.t1 (a TEXT, b TEXT, c TEXT, id SERIAL PRIMARY KEY, e TEXT, f TEXT);
INSERT INTO public.t1 (e) VALUES ('x'), ('y'), ('z');
Code to duplicate values without the primary key column:
DO $$
DECLARE
_table_schema TEXT := 'public';
_table_name TEXT := 't1';
_pk_column_name TEXT := 'id';
_columns TEXT;
BEGIN
SELECT STRING_AGG(column_name, ',')
INTO _columns
FROM information_schema.columns
WHERE table_name = _table_name
AND table_schema = _table_schema
AND column_name <> _pk_column_name;
EXECUTE FORMAT('INSERT INTO %1$s.%2$s (%3$s) SELECT %3$s FROM %1$s.%2$s', _table_schema, _table_name, _columns);
END $$
The query it creates and runs is: INSERT INTO public.t1 (a,b,c,e,f) SELECT a,b,c,e,f FROM public.t1. It's selected all the columns apart from the PK one. You could put this code in a function and use it for any table you wanted, or just use it like this and edit it for whatever table.
I am updating a table which has 4 columns together as primary key.
|Col1|Col2|Col3|Col4|val|
| 1| 2| 3| 4|234|
Col 1-4 make primary key
I need to update Col1 in some rows. But some rows already have the value which i want to update. Thus when i run the query it gives :
ERROR: duplicate key value violates unique constraint "datavalue_pkey"
DETAIL: Key (Col1, Col2, Col3, Col4)=(609, 76911, 164, 1) already exists.
How can i ignore the cases which are already present so that update query runs fully??
Update Query :
update datavalue dv set Col1 = 6009
where concat( dv.Col1 ,'-',dv.Col2,'-',Col3,'-',dv.Col4)
in (
Select concatenated id ... from same table
)
Thanks
POSTGRES - 9.5.12
Depending on your application, I would suggest to write a function, but I guess what you're looking for is something like this (quick & dirty):
Test table and dataset:
CREATE TEMP TABLE t (id INT UNIQUE, des TEXT);
INSERT INTO t VALUES (1,'foo'),(2,'bar');
Update ignoring conflicts.
DO $$
DECLARE r RECORD;
BEGIN
FOR r IN SELECT * FROM t LOOP
BEGIN
UPDATE t SET id = 2 WHERE des = 'foo' AND id = r.id;
UPDATE t SET des = 'bar2' WHERE id = 2 AND id = r.id;
EXCEPTION WHEN unique_violation THEN
RAISE NOTICE 'Oups .. there was a conflict on % - %',r.id,r.des;
END;
END LOOP;
END$$;
If I understand your example correctly, you should be able to use a subquery to simply exclude rows with the Col1 value you are trying to set.
UPDATE datavalue SET Col1 = '6009'
WHERE [your conditions]
AND Col1 NOT IN (SELECT Col1 FROM datavalue WHERE Col1 = '6009')
Was getting this error each and every time tried to execute a DROP Table if exists
Step 1: Created a Table
CREATE TABLE Work_Tables.dbo.Drop_Table_Test (RowID INT IDENTITY(1,1), Data VARCHAR(50))
INSERT INTO Work_Tables.dbo.Drop_Table_Test
SELECT 'Test' UNION
SELECT 'Test1' UNION
SELECT 'Test2' UNION
SELECT 'Test3'
Step 2: Wrote a IF Exists block to check if the Table exists.
IF EXISTS (SELECT 1 FROM Work_Tables.dbo.SysObjects WHERE NAME LIKE 'Drop_Table_Test' AND XType = 'U')
BEGIN
PRINT 'IN'
DROP TABLE Work_Tables.dbo.Drop_Table_Test
END
CREATE TABLE Work_Tables.dbo.Drop_Table_Test (RowID INT IDENTITY(1,1), Data VARCHAR(50), NAME VARCHAR(20), PreCheck INT)
INSERT INTO Work_Tables.dbo.Drop_Table_Test (Data, Name, PreCheck)
SELECT 'Test','SRK',1 UNION
SELECT 'Test1','Daya',2 UNION
SELECT 'Test2','Dinesh',3 UNION
SELECT 'Test3','Suresh',4
On running the Step 2 Code its obvious the Table has to be Dropped and recreated with the same name but it didn't even enter the Begin End block.
I feel that its because have added few more columns in the second try, but still not clear why it should have problems as we are to DROP the table.
You can not drop and create the same table in the same batch in SQL Server.
Break your code up into separate batches so the table can be dropped before you try and recreate it. Add GO after END in your BEGIN / END statement.
IF EXISTS (SELECT 1 FROM Work_Tables.dbo.SysObjects WHERE NAME LIKE 'Drop_Table_Test' AND XType = 'U')
BEGIN
PRINT 'IN'
DROP TABLE Work_Tables.dbo.Drop_Table_Test
END
GO --Add this...
....
Straight from Microsoft's Documentation:
DROP TABLE and CREATE TABLE should not be executed on the same table in the same batch. Otherwise an unexpected error may occur.
You can try to use this syntax:
IF OBJECT_ID('dbo.Drop_Table_Test', 'U') IS NOT NULL
DROP TABLE dbo.Drop_Table_Test;
IF EXISTS will drop the table only when your table Drop_Table_Test does not contain any row. In case if it contains the data then it will not drop the table.
Hello what is the easiest way to duplicate a DB record over the same table?
My problem is that the table where I am doing this has many column, like 100+, and I don't like how the solution looks like. Here is what I do (this is inside plpqsql function):
...
1. duplicate record
INSERT INTO history
(SELECT NEXTVAL('history_id_seq'), col_1, col_2, ... , col_100)
FROM history
WHERE history_id = 1234
ORDER BY datetime DESC
LIMIT 1)
RETURNING
history_id INTO new_history_id;
2. update some columns
UPDATE history
SET
col_5 = 'test_5',
col_23 = 'test_23',
datetime = CURRENT_TIMESTAMP
WHERE history_id = new_history_id;
Here are the problems I am attempting to solve
Listing all these 100+ columns looks lame
When new column is added eventually the function should be updated too
On separate DB instances the column order might differ, which would cause the function fail
I am not sure if I can list them once more (solving issue 3) like insert into <table> (<columns_list>) values (<query>) but then the query looks even uglier.
I would like to achieve something like 'insert into ', but this seems impossible the unique primary key constraint will raise a duplication error.
Any suggestions?
Thanks in advance for you time.
This isn't pretty or particularly optimized but there are a couple of ways to go about this. Ideally, you might want to do this all in an UPDATE trigger though you could implement a duplication function something like this:
-- create source table
CREATE TABLE history (history_id serial not null primary key, col_2 int, col_3 int, col_4 int, datetime timestamptz default now());
-- add some data
INSERT INTO history (col_2, col_3, col_4)
SELECT g, g * 10, g * 100 FROM generate_series(1, 100) AS g;
-- function to duplicate record
CREATE OR REPLACE FUNCTION fn_history_duplicate(p_history_id integer) RETURNS SETOF history AS
$BODY$
DECLARE
cols text;
insert_statement text;
BEGIN
-- build list of columns
SELECT array_to_string(array_agg(column_name::name), ',') INTO cols
FROM information_schema.columns
WHERE (table_schema, table_name) = ('public', 'history')
AND column_name <> 'history_id';
-- build insert statement
insert_statement := 'INSERT INTO history (' || cols || ') SELECT ' || cols || ' FROM history WHERE history_id = $1 RETURNING *';
-- execute statement
RETURN QUERY EXECUTE insert_statement USING p_history_id;
RETURN;
END;
$BODY$
LANGUAGE 'plpgsql';
-- test
SELECT * FROM fn_history_duplicate(1);
history_id | col_2 | col_3 | col_4 | datetime
------------+-------+-------+-------+-------------------------------
101 | 1 | 10 | 100 | 2013-04-15 14:56:11.131507+00
(1 row)
As I noted in my original comment, you might also take a look at the colnames extension as an alternative to querying the information schema.
You don't need the update anyway, you can supply the constant values directly in the SELECT statement:
INSERT INTO history
SELECT NEXTVAL('history_id_seq'),
col_1,
col_2,
col_3,
col_4,
'test_5',
...
'test_23',
...,
col_100
FROM history
WHERE history_sid = 1234
ORDER BY datetime DESC
LIMIT 1
RETURNING history_sid INTO new_history_sid;