is it possible to have some oracle objects like collections in memory than populated and use it in other pl/sql blocks? something like:
create type myType as objects
(id number, name varchar2(40));
create type myTabType is table of myType;
procedure populateMyTabType is
vType myTabType := myTabType();
begin
for i in (select id,name
from employees) loop
vType.extend;
vType(vType.last) := myType(i.id, i.name);
end loop;
end;
and now I would like throgh a pl/sql block to iterate through myTabType.
can I do this? how?
Thank you
For example like this:
create type myType as object
(id number, name varchar2(40));
create type myTabType is table of myType;
create or replace function populateMyTabType
return myTabType
is
vType myTabType := myTabType();
begin
for i in (select 1 id,'name' name
from dual) loop
vType.extend;
vType(vType.COUNT) := myType(i.id, i.name);
end loop;
return vType;
end populateMyTabType;
create or replace procedure iterateMyTabType(
p_mytype IN myTabType
)
is
begin
for i in p_mytype.FIRST..p_mytype.LAST
LOOP
dbms_output.put_line(p_mytype(i).id || ' ' || p_mytype(i).name);
end loop;
end iterateMyTabType;
begin
iterateMyTabType(populateMyTabType);
end;
1 name
But you need to use bulk collect into if you can.
PS: pay attention I changed the select statement in the for clause in the populateMyTabType you need to use your own select.
Related
I am trying to write function in postgresql, that creates temp_table with columns table_name text, table_rec jsonb and fill it through for loop with table names from my table containing names of tables and records in json. I have the for loop in string and I want to execute it. But it doesnt work.
I have variable rec record, sql_query text and tab_name text and I want to do this:
CREATE OR REPLACE FUNCTION public.test51(
)
RETURNS TABLE(tabel_name text, record_json jsonb)
LANGUAGE 'plpgsql'
COST 100
VOLATILE
ROWS 1000
AS $BODY$
declare
rec record;
tabel_name text;
tabel_names text[];
counter integer := 1;
sql_query text;
limit_for_sending integer;
rec_count integer;
begin
select into tabel_names array(select "TABLE_NAME" from public."TABLES");
create temp table temp_tab(tab_nam text, recik jsonb);
while array_length(tabel_names, 1) >= counter loop
tabel_name := '"' || tabel_names[counter] || '"';
select into limit_for_sending "TABLE_LIMIT_FOR_SENDING_DATA" from public."TABLES" where "TABLE_NAME" = tabel_name;
sql_query := 'select count(*) from public.' || tabel_name;
execute sql_query into rec_count;
if (rec_count >= limit_for_sending and limit_for_sending is not null) then
sql_query := 'for rec in select * from public.' || tabel_name || '
loop
insert into temp_tab
select ' || tabel_name || ', to_jsonb(rec);
end loop';
execute sql_query;
end if;
counter := counter + 1;
end loop;
return query
select * from temp_tabik;
drop table temp_tabik;
end;
$BODY$;
Thank you for response.
It seems you have some table that contains the information for which tables you want to return all rows as JSONB. And that meta-table also contains a column that sets a threshold under which the rows should not be returned.
You don't need the temp table or an array to store the table names. You can iterate through the query on the TABLES table and run the dynamic SQL directly in that loop.
return query in PL/pgSQL doesn't terminate the function, it just appends the result of the query to the result of the function.
Dynamic SQL is best created using the format() function because it is easier to read and using the %I placeholder will properly deal with quoted identifiers (which is really important as you are using those dreaded upper case table names)
As far as I can tell, your function can be simplified to:
CREATE OR REPLACE FUNCTION public.test51()
RETURNS TABLE(tabel_name text, record_json jsonb)
LANGUAGE plpgsql
AS
$BODY$
declare
rec record;
sql_query text;
rec_count bigint;
begin
for rec in
select "TABLE_NAME" as table_name, "TABLE_LIMIT_FOR_SENDING_DATA" as rec_limit
from public."TABLES"
loop
if rec.rec_limit is not null then
execute format('select count(*) from %I', rec.table_name)
into rec_count;
end if;
if (rec.rec_limit is not null and rec_count >= rec.rec_limit) then
sql_query := format('select %L, to_jsonb(t) from %I as t', rec.table_name, rec.table_name);
return query execute sql_query;
end if;
end loop;
end;
$BODY$;
Some notes
the language name is an identifier and should not be enclosed in single quotes. This syntax is deprecated and might be removed in a future version so don't get used to it.
you should really avoid those dreaded quoted identifiers. They are much more trouble than they are worth it. See the Postgres wiki for details.
So I have a function select_id_from_table(_t). It chooses certain column of the table (_t) where _t is a table name as a parameter.
I call it like SELECT select_id_from_table('tablename').Now I want to create another function where the function does something like this:
CREATE OR REPLACE FUNCTION myfunction(_u type1, _t type2) returns void as $$
BEGIN
UPDATE (_u) set score=score+1 where _u.id in _t.id;
END;
$$ LANGUAGE plpgsql
The problem is it can not pass the parameter properly. And also what should type1 and type2 be? _u and _t are both names of tables. I have tried:
$$begin
create temp table lid as (select * from select_id_from_table(_t));
execute format ('update '||quote_ident(_u) ||' set score= score+1 where
'||quote_ident(_u) ||'.id_ in (
select * from select_id_from_table ('||quote_ident(_t)||') as
abc )');
end;$$
I also tried creating a temp table, select select_id_from_table(_t)into that temp table and make reference of it later. But I still don't know how to quote it in execute format(''). Any ideas would be appreciated.
I assume that select_id_from_table is a function returning SETOF <something> and that the return type can be cast to text.
I didn't test it, but I would do it similar to this:
DECLARE
in_clause text;
BEGIN
SELECT string_agg(quote_literal(t::text), ', ') INTO in_clause
FROM select_id_from_table(_u) s(t);
EXECUTE format ('UPDATE %I
SET score = score + 1
WHERE %I.id_ =ANY (' || in_clause || ')',
_u, _u);
END;
I'm having trouble referencing record variable type columns dynamically. I found loads of tricks online, but with regards to triggers mostly and I really hope the answer isn't "it can't be done"... I've got a very specific and simple need, see my example code below;
First I have an array containing a list of column names called "lCols". I loop through a record variable to traverse my data, replacing values in a paragraph which exactly match my column names.
DECLARE lTotalRec RECORD;
DECLARE lSQL text;
DECLARE lCols varchar[];
p_paragraph:= 'I am [names] and my surname is [surname]';
lSQL :=
'select
p.names,
p.surname
from
person p
';
FOR lTotalRec IN
execute lSQL
LOOP
-- Loop through the already created array of columns to replace the values in the paragraph
FOREACH lVal IN ARRAY lCols
LOOP
p_paragraph := replace(p_paragraph,'[' || lVal || ']',lTotalRec.lVal); -- This is where my problem is, because lVal is not a column of lTotalRec directly like this
END LOOP;
RETURN NEXT;
END LOOP;
My return value is the paragraph amended for each record in "lTotalRec"
You could convert your record to a json value using the row_to_json() function. Once in this format, you can extract columns by name, using the -> and ->> operators.
In Postgres 9.4 and up, you can also make use of the more efficient jsonb type.
DECLARE lJsonRec jsonb;
...
FOR lTotalRec IN
execute lSQL
LOOP
lJsonRec := row_to_json(lTotalRec)::jsonb;
FOREACH lVal IN ARRAY lCols
LOOP
p_paragraph := replace(p_paragraph, '[' || lVal || ']', lJsonRec->>lVal);
END LOOP;
RETURN NEXT;
END LOOP;
See the documentation for more details.
You can convert a row to JSON using row_to_json(), and then retrieve the column names using json_object_keys().
Here's an example:
drop table if exists TestTable;
create table TestTable (col1 text, col2 text);
insert into TestTable values ('a1', 'b1'), ('a2', 'b2');
do $$declare
sql text;
rec jsonb;
col text;
val text;
begin
sql := 'select row_to_json(row) from (select * from TestTable) row';
for rec in execute sql loop
for col in select * from jsonb_object_keys(rec) loop
val := rec->>col;
raise notice 'col=% val=%', col, val;
end loop;
end loop;
end$$;
This prints:
NOTICE: col=col1 val=a1
NOTICE: col=col2 val=b1
NOTICE: col=col1 val=a2
NOTICE: col=col2 val=b2
DO
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'm trying to write a function in PL/PgSQL that have to work with a table it receives as a parameter.
I use EXECUTE..INTO..USING statements within the function definition to build dynamic queries (it's the only way I know to do this) but ... I encountered a problem with RECORD data types.
Let's consider the follow (extremely simplified) example.
-- A table with some values.
DROP TABLE IF EXISTS table1;
CREATE TABLE table1 (
code INT,
descr TEXT
);
INSERT INTO table1 VALUES ('1','a');
INSERT INTO table1 VALUES ('2','b');
-- The function code.
DROP FUNCTION IF EXISTS foo (TEXT);
CREATE FUNCTION foo (tbl_name TEXT) RETURNS VOID AS $$
DECLARE
r RECORD;
d TEXT;
BEGIN
FOR r IN
EXECUTE 'SELECT * FROM ' || tbl_name
LOOP
--SELECT r.descr INTO d; --IT WORK
EXECUTE 'SELECT ($1)' || '.descr' INTO d USING r; --IT DOES NOT WORK
RAISE NOTICE '%', d;
END LOOP;
END;
$$ LANGUAGE plpgsql STRICT;
-- Call foo function on table1
SELECT foo('table1');
It output the following error:
ERROR: could not identify column "descr" in record data type
although the syntax I used seems valid to me. I can't use the static select (commented in the example) because I want to dinamically refer the columns names.
So..someone know what's wrong with the above code?
It's true. You cannot to use type record outside PL/pgSQL space.
RECORD value is valid only in plpgsql.
you can do
EXECUTE 'SELECT $1.descr' INTO d USING r::text::xx;
$1 should be inside the || ,like || $1 || and give spaces properly then it will work.
BEGIN
EXECUTE ' delete from ' || quote_ident($1) || ' where condition ';
END;