I have problem when create function for trigger. I want to UPDATE inserted value BEFORE INSERT data to DB.
My code look like this:
CREATE OR REPLACE FUNCTION test_func()
RETURNS TRIGGER AS
$$
DECLARE cnt INTEGER;
BEGIN
cnt := COUNT(*) FROM sample_tbl WHERE id = NEW.id AND created_date = NEW.created_date;
NEW.current_order := cnt + 1; // I want to set value of sample_tbl.current_order automatically
END
$$ LANGUAGE plpgsql;
CREATE TRIGGER test_trigger
BEFORE INSERT
ON test_tbl
FOR EACH ROW
EXECUTE PROCEDURE test_func();
I inserted data then IDE said:
control reached end of trigger procedure without RETURN
Where: PL/pgSQL function test_func()
The error says that you must return something from the Trigger ( either NEW or NULL )
There's no Trigger needed for this. A simple View using this select query will give you the required result
--create or replace view sample_view as
select t.id, t.created_date,
row_number() OVER ( partition by id,created_date order by id ) as current_order
FROM sample_tbl t;
This will exactly match the records if updated using a Trigger
CREATE OR REPLACE FUNCTION test_func()
RETURNS TRIGGER AS
$$
DECLARE cnt INTEGER;
BEGIN
select COUNT(*) INTO cnt FROM sample_tbl WHERE id = NEW.id
AND created_date = NEW.created_date;
NEW.current_order := cnt + 1;
RETURN NEW; --required
END
$$ LANGUAGE plpgsql;
Demo
Your trigger function is just missing RETURN NEW; statement:
CREATE OR REPLACE FUNCTION test_func()
RETURNS TRIGGER AS
$$
DECLARE cnt INTEGER;
BEGIN
cnt := COUNT(*) FROM sample_tbl WHERE id = NEW.id AND created_date = NEW.created_date;
NEW.current_order := cnt + 1;
RETURN NEW;
END
$$ LANGUAGE plpgsql;
Related
I have the following postgres stored procedure:
CREATE OR REPLACE PROCEDURE
schema.MyProcedure()
AS $$
DECLARE
RowCount int;
BEGIN
SELECT cnt INTO RowCount
FROM (
SELECT COUNT(*) AS cnt
FROM MySchema.MyTable
) AS sub;
RAISE NOTICE 'RowCount: %', RowCount;
END;
$$
LANGUAGE plpgsql;
which "prints" out the row count of the static table MySchema.MyTable. How can it make it so I pass the Table and Schema name as an input.
eg:
CREATE OR REPLACE PROCEDURE
schema.MyProcedure(MySchema_In varchar, MyTable_In varchar)
AS $$
DECLARE
RowCount int;
BEGIN
SELECT cnt INTO RowCount
FROM (
SELECT COUNT(*) AS cnt
FROM || **MySchema_In** || . || **MyTable_In** ||
) AS sub;
RAISE NOTICE 'RowCount: %', RowCount;
END;
$$
LANGUAGE plpgsql;
You should use format() instead of concatenating the strings with || and then EXECUTE ... INTO to get the query's result, e.g.
CREATE OR REPLACE PROCEDURE MyProcedure(MySchema_In varchar, MyTable_In varchar)
AS $$
DECLARE RowCount int;
BEGIN
EXECUTE FORMAT('SELECT count(*) FROM %I.%I',$1,$2) INTO RowCount;
RAISE NOTICE 'RowCount: %', RowCount;
END;
$$
LANGUAGE plpgsql;
I am trying to assign a variable the result of a query in a postgres stored procedure.
Here is what I am trying to run:
CREATE OR Replace PROCEDURE schema.MyProcedure()
AS $$
DECLARE
RowCount int = 100;
BEGIN
select cnt into RowCount
from (
Select count(*) as cnt
From schema.MyTable
) ;
RAISE NOTICE 'RowCount: %', RowCount;
END;
$$
LANGUAGE plpgsql;
schema.MyTable is just some arbitrary table name but the script is not displaying anything, not even the random value I assigned RowCount to (100).
What am I doing wrong?
Thanks
You need an alias for the subquery, for example : as sub
CREATE OR Replace PROCEDURE schema.MyProcedure()
AS $$
DECLARE
RowCount int = 100;
BEGIN
select cnt into RowCount
from (
Select count(*) as cnt
From schema.MyTable
) as sub ;
RAISE NOTICE 'RowCount: %', RowCount;
END;
$$
LANGUAGE plpgsql;
You can also assign any variable with a query result in parenthesis.
CREATE OR REPLACE PROCEDURE schema.my_procedure()
AS
$$
DECLARE
row_count BIGINT;
BEGIN
row_count = (SELECT COUNT(*) FROM schema.my_table);
RAISE NOTICE 'RowCount: %', row_count;
END;
$$ LANGUAGE plpgsql;
You should use BIGINT instead of INT.
And it's far better to write your code and table definition with snake_case style as possible.
I am new to using postgresql, I am trying to make a trigger that just inserts in the Employee table and also inserts in the Vacations table, but I don't know how to assign the values, I do it like that in sql but here I really don't know how
CREATE FUNCTION SP_InsertaVacacionesEmpleado() RETURNS TRIGGER
AS
$$
DECLARE _NumeroIdentificacion INTEGER;
DECLARE _FechaEntrada DATE;
BEGIN
SET _NumeroIdentificacion = SELECT NEW.NumeroIdentificacion FROM "Empleado"
SET _FechaEntrada = SELECT NEW.FechaEntrada FROM "Empleado"
INSERT INTO Vacaciones VALUES(_NumeroIdentificacion, _FechaEntrada, '', 0);
RETURN NEW;
END
$$
LANGUAGE plpgsql
As documented in the manual assignment is done using the := operator, e.g.:
some_variable := 42;
However to assign one or more variables from the result of a query, use select into, e.g.:
DECLARE
var_1 INTEGER;
var_2 DATE;
BEGIN
select col1, col2
into var_1, var_2
from some_table
...
However neither of that is necessary in a trigger as you can simply use the reference to the NEW record directly in the INSERT statement:
CREATE FUNCTION sp_insertavacacionesempleado()
RETURNS TRIGGER
AS
$$
BEGIN
INSERT INTO Vacaciones (...)
VALUES (NEW.NumeroIdentificacion, NEW.FechaEntrada , '', 0);
RETURN NEW;
END
$$
LANGUAGE plpgsql;
Note that you need to define a row level trigger for this to work:
create trigger ..
before insert on ...
for each row --<< important!
execute procedure sp_insertavacacionesempleado() ;
In Postgres, someone knows how to substitute the value of the variable in a NEW.variable in a trigger?
For instance, I have a variable with value order_code. I want to execute NEW.variable so that it's getting in fact NEW.order_code.
In detailed:
I have a function to obtain the primary key column of a table:
CREATE FUNCTION getPrimaryKey(_table_name VARCHAR(50))
RETURNS SETOF VARCHAR(50) AS $$
DECLARE
primary_key VARCHAR(50);
BEGIN
FOR primary_key IN SELECT a.attname
FROM pg_index i
JOIN pg_attribute a ON a.attrelid = i.indrelid
AND a.attnum = ANY(i.indkey)
WHERE i.indrelid = _table_name::regclass
AND i.indisprimary LOOP
RETURN NEXT primary_key;
END LOOP;
END;
$$ LANGUAGE plpgsql;
Then I have a trigger to collect some info when an INSERT is done in a table. The procedure in the trigger is called from several triggers from different tables. That's why it's so generic and I have this need.
What I want is to obtain the primary key of the object inserted.
CREATE FUNCTION logAudit()
RETURNS trigger AS $$
DECLARE primary_key VARCHAR(50);
BEGIN
primary_key := getprimarykey(TG_TABLE_NAME::VARCHAR(50));
INSERT INTO test VALUES (TG_TABLE_NAME);
INSERT INTO test VALUES (NEW.primary_key);
RETURN NULL;
END;
$$ LANGUAGE plpgsql;
CREATE TRIGGER audit_in_client
AFTER INSERT ON tb_client
FOR EACH STATEMENT EXECUTE PROCEDURE logAudit();
The NEW.primary_key is what is causing me issues. I expect primary_key to be the column name of the source table where the insert happened. What I want in NEW.primary_key is to actually use the value in the variable.
Here is the example of anonymous pl/pgsql block which doing something what you want:
do $$
declare
v pg_database = (pg_database) from pg_database where datname = 'template1';
fname text = 'datname';
n text;
begin
n := to_jsonb(v)->>fname;
raise info '%', n;
end $$;
Output:
INFO: template1
It is working example. In your trigger function it could be something like
declare
pk_name text;
pk_value text;
begin
pk_name := getprimarykey(TG_TABLE_NAME::VARCHAR(50));
pk_value := to_jsonb(NEW) ->> pk_name;
-- Do what you want with pk_value here
return null;
end $$;
I want to create stored procedure to check count of query result. Then if count is > 0 to execute some query to delete records in other table. Below see what i got so far.
CREATE OR REPLACE PROCEDURE myprocedure(tableName VARCHAR, age INT, secondTable VARCHAR)
AS
$$
declare cnt := SELECT COUNT(*) FROM %tableName% WHERE ageID =%id%;
declare result;
BEGIN
EXECUTE cnt;
IF cnt >= 1 THEN
result := SELECT ID FROM %tableName% WHERE ageID =%id%
--remove records from secondTable
EXECUTE DELETE FROM %secondTable% WHERE ID IN (result)
END IF;
COMMIT;
END;
As documented in the manual you can't "reference" a variable with %tableName% and you certainly can not use a variable within a SQL statement for an identifier. You will need to use dynamic SQL.
You also got the DECLARE part completely wrong. You only write the keyword once, and you have to define a data type for the variables.
To create SQL strings that contain identifier, use format() and the %I placeholder to properly deal with identifiers that need quoting.
CREATE OR REPLACE PROCEDURE myprocedure(p_tablename VARCHAR, p_age INT, p_secondtable VARCHAR)
AS
$$
declare
l_sql text;
cnt integer;
BEGIN
l_sql := format('select count(*) from %I where ageid = :1', p_tablename);
EXECUTE l_sql
using p_age
into cnt;
IF cnt >= 1 THEN
l_sql := format('DELETE FROM %I WHERE ID IN (SELECT id FROM %I where ageid = :1)', p_secondtable, p_tablename);
EXECUTE l_sql using p_age;
END IF;
$$
language plpgsql;
But checking for the count before doing the delete is pretty pointless, you can simply that to a single DELETE statement:
CREATE OR REPLACE PROCEDURE myprocedure(p_tablename VARCHAR, p_age INT, p_secondtable VARCHAR)
AS
$$
declare
l_sql text;
cnt integer;
BEGIN
l_sql := format('DELETE FROM %I WHERE id IN (SELECT t.id FROM %I as t where t.ageid = :1)', p_secondtable, p_tablename);
EXECUTE l_sql using p_age;
END IF;
$$
language plpgsql;
Because the DELETE statement won't delete anything if the sub-select doesn't return any rows (which would be the case for cnt = 0). And you only need to query the first table once.