I'm trying to create a procedure that given a table name, it will create a sequence and auto incrementing trigger, all using variables based on the table name.
Code :
CREATE OR REPLACE procedure CREATE_SEQUENTIAL_TR(table_name VARCHAR)
is -- Tried using declare but it wouldn't accept
coluna_cod varchar(100 char);
begin
--Finding the cod column name for this table first
--They start with "PK_CD"
select
COLUMN_NAME
into
coluna_cod
from
ALL_TAB_COLUMNS
where
TABLE_NAME=table_name
and COLUMN_NAME like "PK_CD%";
--Creating the sequence obj
drop sequence "cod" || table_name;
create sequence "cod" || table_name;
--Now creating the trigger
create or replace trigger "cod" || table_name || "tr"
before
UPDATE or INSERT on table_name
for each row
declare
cod number := coluna_cod;
tr_name varchar(100 char) := "cod" || table_name
begin
if UPDATING then
if :new.cod != :old.cod then
:new.cod := :old.cod;
end if;
else -- inserting
:new.cod := tr_name.nextval();
end if;
end;
end;
The complexity of this ended up quite out of the scope of my knowledge.
At the moment it is giving an error on drop sequence "cod" || table_name (Unexpected DROP symbol found) but I'm sure I have made other errors.
Can someone help me figure this logic out?
You can't put DDL statements (like drop or create or alter) directly inside a PL/SQL block. If you want to do DDL inside PL/SQL, you can do an execute immediate:
declare
begin
drop sequence X; -- error
execute immediate 'drop sequence X'; -- works fine
end;
/
Related
i'm creating a trigger that triggers on INSERT on a table,
and i wish to log the structure of tables inserted so i wrote this Function
CREATE OR REPLACE FUNCTION update_table_log_received()
RETURNS TRIGGER AS $$
DECLARE
added_column TEXT;
target_table_name TEXT;
old_column text;
BEGIN
-- Check if a new column has been added
IF (TG_OP = 'INSERT') THEN
added_column := NEW."COLUMN_NAME";
target_table_name := NEW."TABLE_NAME";
END IF;
SELECT column_name into old_column
FROM information_schema."columns"
WHERE table_schema = 'items'
and table_name = LOWER(NEW."TABLE_NAME")
and column_name = LOWER(NEW."COLUMN_NAME");
if (coalesce(old_column,'')='' or old_column='' or old_column = added_column) THEN
-- If a new column has been added
IF (Lower(added_column) != 'sync') then
-- Add the new column to the target table
EXECUTE 'ALTER TABLE items.' || LOWER(target_table_name)|| ' ADD COLUMN ' || LOWER(added_column) || ' VARCHAR(50)';
END IF;
end if;
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
executed by this TRIGGER :
CREATE TRIGGER update_table_log_received_trigger
AFTER INSERT
ON items."TABLE_LOG_RECEIVED"
FOR EACH ROW
EXECUTE FUNCTION update_table_log_received();
the returned exception is the following :
! ERROR: the column « x » of the relation « y » already exists
Where: instruction SQL « ALTER TABLE items. ADD COLUMN x VARCHAR(50) »
my problem now is that it isn't supposed to pass the If checks (i pasted the code after many alterations i have two if conditions that do the same thing just because),
i debugged and logged the statements to note that the select query inside my function returns null apparently.
i also tried to use "USING NEW" but i am no expert so i couldn't make it work
is it a problem with the declared variable not being populated from the "NEW" record or am i executing the select statement wrong ?
EDIT : tl;dr for my problem, I would like to update a table in Database2 whenever the same table (that had the same structre) is altered from Database1, be it added column or changed column, at this point iI'm stuck at the first problem to add the column.
I am logging my tables' structures as strings into a new table and syncing that with Database2 to then have the trigger alter the same altered table from Database1, hope this makes more sense now.
Database1 log_table that logs all my tables' structures:
Database2 log_table_received that is a copy of log_table that executes
the trigger whenever new values are inserted;
Try this syntax:
CREATE OR REPLACE FUNCTION update_table_log_received()
RETURNS TRIGGER AS $$
DECLARE
added_column TEXT;
target_table_name TEXT;
old_column text;
BEGIN
-- Check if a new column has been added
IF (TG_OP = 'INSERT') THEN
added_column := new."column_name";
target_table_name := new."table_name";
END IF;
if not exists(select 1 from information_schema."columns" where table_name = target_table_name and column_name = added_column)
then
EXECUTE 'ALTER TABLE items.' || LOWER(target_table_name)|| ' ADD COLUMN ' || LOWER(added_column) || ' VARCHAR(50)';
end if;
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
I tried on my DB this is works. You can change some details yourself.
Fixed; Question should have been :
How to select tables & table columns inside function in postgresql.
References:
How to add column if not exists on PostgreSQL?
How to check if a table exists in a given schema
How to get a list column names and datatypes of a table in PostgreSQL?
Basically information_schema can only be accessed by owner meaning the user or (i) see the result when i query it but it returns FALSE when executed inside a script more details here :
https://stackoverflow.com/a/24089729/15170264
Full trigger after fix with CTE to query the pg_catalog also added ADD COLUMN IF NOT EXISTS in my Execute query just to be safe
CREATE OR REPLACE FUNCTION update_table_log_received()
RETURNS TRIGGER AS $$
DECLARE
added_column TEXT;
target_table_name TEXT;
old_column varchar;
old_table varchar;
BEGIN
-- Check if a new column has been added
IF (TG_OP = 'INSERT') THEN
added_column := NEW."COLUMN_NAME";
target_table_name := NEW."TABLE_NAME";
END IF;
/*
* --------------- --CTE to find Columns of table "Target_table_name" from pg_catalog
*/
WITH cte_tables AS (
SELECT
pg_attribute.attname AS column_name,
pg_catalog.format_type(pg_attribute.atttypid, pg_attribute.atttypmod) AS data_type
FROM
pg_catalog.pg_attribute
INNER JOIN
pg_catalog.pg_class ON pg_class.oid = pg_attribute.attrelid
INNER JOIN
pg_catalog.pg_namespace ON pg_namespace.oid = pg_class.relnamespace
WHERE
pg_attribute.attnum > 0
AND NOT pg_attribute.attisdropped
AND pg_namespace.nspname = 'items'
AND pg_class.relname = 'trace'
ORDER BY
attnum ASC
)
select column_name into old_column from cte_tables where
column_name=LOWER(added_column);
if (old_column is null ) then
-- Add the new column to the target table
old_column := added_column;
EXECUTE 'ALTER TABLE items.' || LOWER(target_table_name)|| ' ADD COLUMN IF NOT EXISTS ' || LOWER(added_column) || ' VARCHAR(50)';
else
old_column := added_column || 'already exists ! ';
END IF;
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
create TRIGGER update_table_log_received_trigger
AFTER INSERT
ON items."TABLE_LOG_RECEIVED"
FOR EACH ROW
EXECUTE FUNCTION update_table_log_received();
Variable old_column stores the else condition message but i do not return it, would have if it was a simple function.
I'm new in postgres, I'm creating a procedure to rename table constraint names using the REPLACE(). If I test all the variables in this procedure the data is there and if I replace it manually it can. The problem is when this procedure is running the constraint name doesn't change.
create or replace procedure public.rename_existing_constraint_table(in table_name text, in date_now text, in list_constraint text[])
as $$ declare
const text;
table_rename text;
begin
table_rename := (select concat(table_name, '_', date_now));
if array_length(list_constraint, 1) >= 1 then
foreach const in array list_constraint loop
execute 'alter table if exists ' || table_name || ' RENAME CONSTRAINT ' || const || ' to ' || replace(const, table_name, table_rename);
end loop;
end if;
end $$
language plpgsql;
duplicate error because the data was not successfully renamed, it should be
app_devlogdetail_pkey to app_devlogdetail_20221214_pkey
psycopg2.errors.DuplicateTable: relation "app_devlogdetail_pkey" already exists
CONTEXT: SQL statement "alter table if exists app_devlogdetail_20221214 RENAME CONSTRAINT app_devlogdetail_pkey to app_devlogdetail_pkey"
PL/pgSQL function rename_existing_constraint_table(text,text,text[]) line 10 at EXECUTE
I have tried running the REPLACE() outside the procedure and it runs normally and the data can be changed, but when it is run inside the procedure to be executed the REPLACE() can't changed data. How to make the REPLACE() can run and the data can be changed or is there some other way around it?
I am trying to build a package that will take in a table of table names and either drop from or delete those tables. I am using dynamic sql, and dropping or deleting the tables works, but I need both the procedures to loop through all of the table names passed back to it.
I've tried mulitple ways - including trying to create a FOR Loop and a cursor. Here is a similar function I wrote in PostgreSQL that works but I'm having trouble translating it to Oracle.
Here is my function in PostgreSQL that works:
CREATE OR REPLACE FUNCTION drop_tables_for_stnd_mod_build(tablenames text)
RETURNS void
LANGUAGE plpgsql
AS $function$
DECLARE
tab_name RECORD;
BEGIN
FOR tab_name IN EXECUTE 'SELECT table_name FROM ' || tablenames
LOOP
EXECUTE 'DROP TABLE ' || tab_name.table_name || ' CASCADE';
END LOOP;
END;
$function$
;
And the procedure I'm writing as part of a package in Oracle
CREATE OR REPLACE PACKAGE BODY stnd_build_table_cleanup
AS
PROCEDURE drop_tables(table_in CLOB)
IS
TYPE cur_type is REF CURSOR;
c cur_type;
query_string VARCHAR(300);
loop_string VARCHAR(300);
table_name VARCHAR(100);
BEGIN
loop_string := 'SELECT tablenames FROM :table';
OPEN c FOR loop_string USING table_in;
LOOP
FETCH c INTO table_name;
query_string := 'DROP TABLE ' || table_name || ' CASCADE CONSTRAINTS';
-- dbms_output.PUT_LINE (query_string);
EXECUTE IMMEDIATE query_string;
EXIT WHEN c%NOTFOUND;
END LOOP ;
CLOSE c;
END drop_tables;
Here is the error I get when I try to call my function: Error report -
ORA-00903: invalid table name
ORA-06512: at "AMS_NYS.STND_BUILD_TABLE_CLEANUP", line 13
ORA-06512: at line 2
00903. 00000 - "invalid table name"
*Cause:
*Action:
Thanks!
Here's one possibility. Note that I coded this as a standalone procedure for simplicity.
CREATE OR REPLACE TYPE table_type IS TABLE OF VARCHAR2(128);
CREATE OR REPLACE PROCEDURE drop_tables(tables_to_drop_in table_type)
IS
BEGIN
FOR i IN tables_to_drop_in.FIRST .. tables_to_drop_in.LAST LOOP
--DBMS_OUTPUT.PUT_LINE(tables_to_drop_in(i));
EXECUTE IMMEDIATE 'DROP TABLE ' || tables_to_drop_in(i) || ' CASCADE CONSTRAINTS';
END LOOP;
END drop_tables;
DECLARE
tables_to_drop table_type;
BEGIN
tables_to_drop := table_type('TBL1','TBL2', 'TBL3');
drop_tables(tables_to_drop);
END;
I need to drop a table only if the table exist, can do it using plsql block
BEGIN
EXECUTE IMMEDIATE 'DROP TABLE <table_name>;
EXCEPTION
WHEN OTHERS THEN
IF SQLCODE != -942 THEN
RAISE;
END IF;
END
But in my case the table name has sysdate (02062017) eg table001_02072017 and i need to delete all such tables with sysdate-1.
How can i do so?
You can find the table with the given pattern from user_tables dictionary table and loop on the result to drop each one by one.
begin
for t in (select table_name from user_tables
where table_name like '%\_'||to_char(sysdate-1,'mmddyyyy') escape '\')
loop
execute immediate 'drop table ' || t.table_name;
end loop;
exception
/* Handle your exceptions here. */
end;
/
Using WHEN OTHERS in your exception handling is discouraged. You should explicitly handle the errors.
Dynamic sql will help you here just use
execute immediate 'drop table ' || table_name;
inside your procedure
CREATE OR REPLACE TRIGGER P88
AFTER INSERT ON reparation
FOR EACH ROW
DECLARE
vope number;
BEGIN
SELECT observation_reparation into vope from repartion;
if(vope IS NULL)THEN
EXECUTE IMMEDIATE 'ALTER TABLE ' || reparation.observations_Reparation || ' MODIFY libelle_piece NVARCHAR2(50)';
END IF;
END;
/
I get this:
error:table or view does not exist.
CREATE OR REPLACE TRIGGER P88
AFTER INSERT ON reparation
FOR EACH ROW
DECLARE
vope number;
BEGIN
SELECT observation_reparation into vope from repartion;
if(vope IS NULL)THEN
EXECUTE IMMEDIATE 'ALTER TABLE reparation RENAME COLUMN observations_Reparation TO libelle_piece';
END IF;
END;
if you also need to change the declaration of the column you will need another ALTER statement
alter table reparation modify (libelle_piece NVARCHAR2(50))