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() ;
Related
I have been working on creating a store procedure that will select data from a table, do some modification to that data, and then I need to insert that modified data into the same table. Take an example my table name is student. My procedure looks like below:
create or replace procedure student_create(p_code varchar)
language plpgsql
as $$
declare
v_student public.student;
begin
select * into v_student from student where code = p_code and is_latest_version is true;
raise notice 'Value: %', v_student;
v_student.id = uuid_generate_v4();
v_student.version_created_at = now();
v_student.version_updated_at = v_student.version_created_at;
raise notice 'Value: %', v_student;
INSERT INTO public.student VALUES(v_student);
end;$$
I am getting errors while calling this procedure:
ERROR: column "id" is of type uuid but expression is of type hotel
LINE 1: INSERT INTO public.hotel VALUES(v_hotel)
I know I can make insert statements like I can get each value from the variable and set it like
INSERT INTO public.student VALUES(v_student.id, v_student.code, v_student.name);
But I don't want to do that because it will become tightly coupled and later if I add another column into the table then I need to add that column into this procedure as well.
Does anyone have idea how can I insert the declared type variable directly into table.
There is no table type, there is only row composite type. Check manual 43.3.4. Row Types.
use row type.
create or replace procedure student_create(p_code text)
language plpgsql
as $$
declare
v_student public.student
begin
for v_student in select * from student where code = p_code and is_latest_version is true
loop
v_student.id = uuid_generate_v4();
v_student.version_created_at = now();
v_student.version_updated_at = v_student.version_created_at;
v_student.is_latest_version = true;
v_student.code = p_code;
INSERT INTO student VALUES(v_student.*);
end loop;
end;$$;
call it: call student_create('hello');
3. use update clause directly.
create or replace procedure student_create_1(p_code text)
language plpgsql as $$
BEGIN
with a as ( select uuid_generate_v4() as id ,
now() as version_created_at,
now() as version_updated_at,
p_code as "code" from student
where code = p_code and is_latest_version is true)
INSERT INTO student(id, version_created_at, version_updated_at, code)
select a.id, a.version_created_at,a.version_updated_at,a."code" from a;
end
$$;
call it: call student_create_1('hello');
fiddle code: here
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 $$;
I'm trying to get a customer id which can be placed in one of ten different tables. I don't want to hard code those table names to find it so I tried postgresql function as follows.
create or replace FUNCTION test() RETURNS SETOF RECORD AS $$
DECLARE
rec record;
BEGIN
select id from schema.table_0201_0228 limit 1 into rec;
return next rec;
select id from schema.table_0301_0331 limit 1 into rec;
return next rec;
END $$ language plpgsql;
select * from test() as (id int)
As I'm not familiar with postgresql function usage, how can I improve the code to replace 'schema.table1' with a variable, loop each table and return the result?
NOTE: table names may change overtime. For example, table_0201_0228 and table_0301_0331 are for February and March respectively.
You need dynamic SQL for that:
create or replace FUNCTION test(p_schema text)
RETURNS table(id int)
AS $$
DECLARE
l_tab record;
l_sql text;
BEGIN
for l_tab in (select schemaname, tablename
from pg_tables
where schemaname = p_schema)
loop
l_sql := format('select id from %I.%I limit 1', l_tab.schemaname, l_tab.tablename);
return query execute l_sql;
end loop;
END $$
language plpgsql;
I made the schema name a parameter, but of course you can hard-code it. As the function is defined as returns table there is no need to specify the column name when using it:
select *
from test('some_schema');
I am trying to have a dynamic variable that I can specify different column's with (depending on some if statements). Explained in code, I am trying to replace this:
IF (TG_TABLE_NAME='this') THEN INSERT INTO table1 (name_id) VALUES id.NEW END IF;
IF (TG_TABLE_NAME='that') THEN INSERT INTO table1 (lastname_id) VALUES id.NEW END IF;
IF (TG_TABLE_NAME='another') THEN INSERT INTO table1 (age_id) VALUES id.NEW END IF;
With this:
DECLARE
varName COLUMN;
BEGIN
IF (TG_TABLE_NAME='this') THEN varName = 'name_id';
ELSE IF (TG_TABLE_NAME='that') THEN varName = 'lastname_id';
ELSE (TG_TABLE_NAME='another') THEN varName = 'age_id';
END IF;
INSERT INTO table1 (varName) VALUES id.NEW;
END;
The INSERT string is just an example, it's actually something longer. I am a beginner at pgSQL. I've seen some examples but I'm only getting more confused. If you can provide an answer that is also more safe from SQL injection that would be awesome.
One way to do what you're looking for is to compose your INSERT statement dynamically based on the named table. The following function approximates the logic you laid out in the question:
CREATE OR REPLACE FUNCTION smart_insert(table_name TEXT) RETURNS VOID AS $$
DECLARE
target TEXT;
statement TEXT;
BEGIN
CASE table_name
WHEN 'this' THEN target := 'name_id';
WHEN 'that' THEN target := 'lastname_id';
WHEN 'another' THEN target := 'age_id';
END CASE;
statement :=
'INSERT INTO '||table_name||'('||target||') VALUES (nextval(''id''));';
EXECUTE statement;
END;
$$ LANGUAGE plpgsql;
Note that I'm using a sequence to populate these tables (the call to nextval). I'm not sure if that is your use case, but hopefully this example is extensible enough for you to modify it to fit your scenario. A contrived demo:
postgres=# SELECT smart_insert('this');
smart_insert
--------------
(1 row)
postgres=# SELECT smart_insert('that');
smart_insert
--------------
(1 row)
postgres=# SELECT name_id FROM this;
name_id
---------
101
(1 row)
postgres=# SELECT lastname_id FROM that;
lastname_id
-------------
102
(1 row)
Your example doesn't make a lot of sense. Probably over-simplified. Anyway, here is a trigger function for the requested functionality that inserts the new id in a selected column of a target table, depending on the triggering table:
CREATE OR REPLACE FUNCTION smart_insert(table_name TEXT)
RETURNS trigger AS
$func$
BEGIN
EXECUTE
'INSERT INTO table1 ('
|| CASE TG_TABLE_NAME
WHEN 'this' THEN 'name_id'
WHEN 'that' THEN 'lastname_id'
WHEN 'another' THEN 'age_id'
END CASE
||') VALUES ($1)'
USING NEW.id;
END
$func$ LANGUAGE plpgsql;
To refer to the id column of the new row, use NEW.id not id.NEW.
To pass a value to dynamic code, use the USING clause of EXECUTE. This is faster and more elegant, avoids casting to text and back and also makes SQL injection impossible.
Don't use many variables and assignments in plpgsql, where this is comparatively expensive.
If the listed columns of the target table don't have non-default column defaults, you don't even need dynamic SQL:
CREATE OR REPLACE FUNCTION smart_insert(table_name TEXT)
RETURNS trigger AS
$func$
BEGIN
INSERT INTO table1 (name_id, lastname_id, age_id)
SELECT CASE WHEN TG_TABLE_NAME = 'this' THEN NEW.id END
, CASE WHEN TG_TABLE_NAME = 'that' THEN NEW.id END
, CASE WHEN TG_TABLE_NAME = 'another' THEN NEW.id END;
END
$func$ LANGUAGE plpgsql;
A CASE expression without ELSE clause defaults to NULL, which is the default column default.
Both variants are safe against SQL injection.
I created a function which writes information about table deletions.
And another function which simply adds a trigger call after delete.
But I would like to store the whole row as string into my table.
According to Postgresql Documentation it should work by adding "OLD.*" into a text based column. But it fails telling me that I try to put too many columns into this table.
OLD is from type RECORD. And i want to have it in my text field like "value1,value2,value3" or it could be "colname:value,colname2:value". I dont care, I just want to see the row which has been deleted.
Another approach can be to log all delete queries from pg_stat_activity. But I don't know how to do that. Simply accessing pg_stat_activity every second would cause too much traffic I guess.
My table is simple:
create table delete_history (date timestamp, tablename varchar(100), data text);
This is my function:
CREATE or REPLACE FUNCTION ondelete() RETURNS TRIGGER AS $$
BEGIN
INSERT INTO delete_history VALUES (CURRENT_TIMESTAMP, TG_TABLE_NAME, OLD.*);
RETURN OLD;
END;
$$ LANGUAGE plpgsql;
This is my trigger:
CREATE OR REPLACE FUNCTION history_create_triggers() RETURNS void
AS $$
DECLARE
r RECORD;
BEGIN
FOR r IN SELECT table_name FROM information_schema.tables WHERE table_schema = 'public' AND table_type='BASE TABLE' LOOP
EXECUTE 'CREATE TRIGGER log_history AFTER DELETE ON public.' || r.table_name || ' FOR EACH ROW EXECUTE PROCEDURE ondelete();';
END LOOP;
END;
$$ LANGUAGE plpgsql;
You can convert type record into text:
CREATE or REPLACE FUNCTION ondelete() RETURNS TRIGGER AS $$
BEGIN
INSERT INTO delete_history VALUES (CURRENT_TIMESTAMP, TG_TABLE_NAME, OLD::text);
RETURN OLD;
END;
$$ LANGUAGE plpgsql;
sql fiddle demo
another approach could be converting your row into JSON with row_to_json function (if you have version 9.2):
CREATE or REPLACE FUNCTION ondelete() RETURNS TRIGGER AS $$
BEGIN
INSERT INTO delete_history VALUES (CURRENT_TIMESTAMP, TG_TABLE_NAME, row_to_json(OLD));
RETURN OLD;
END;
$$ LANGUAGE plpgsql;
sql fiddle demo
Another approach can be convert your data to hstore
CREATE or REPLACE FUNCTION ondelete() RETURNS TRIGGER AS $$
BEGIN
INSERT INTO delete_history VALUES (CURRENT_TIMESTAMP, TG_TABLE_NAME, hstore(OLD));
RETURN OLD;
END;
$$ LANGUAGE plpgsql;
I can't test it now - sqlfiddle is not allowing to use hstore.