What would be the best way to create a stored procedure to apply changes to the database that has about 30 arguments (columns) to be changed?
Right now I'm playing on creating a huge insert query inside the stored procedure that list all the arguments that are passed by the user. Is that the only way or is there a better way for stored procedures this big?
Example:
CREATE OR REPLACE FUNCTION "applyntunesettings"(val1,val2....val30)
RETURNS void AS
BEGIN
INSERT INTO calibrationstable (col1,col2........col20) Values (val1,val2.....val20);
INSERT INTO devicestable (col1,col2,.....col10) values (val21,val22,....val30);
END
Sometimes, row type variables can be convenient. Assuming the tables are "calibrations" and "devices" we can write:
CREATE OR REPLACE FUNCTION applyntunesettings (
_device_name TEXT
, _some_value TEXT
, _other_value TEXT
-- and so on
) RETURNS void AS $$
DECLARE
_calibration calibrations;
_device devices;
BEGIN
_device.name := _device_name;
INSERT INTO devices SELECT _device.*;
_calibration.some_value := _some_value;
_calibration.other_value := _other_value;
INSERT INTO calibrations SELECT _calibration.*;
END $$ LANGUAGE plpgsql;
Related
I have a table that looks like this:
CREATE TABLE label (
hid UUID PRIMARY KEY DEFAULT UUID_GENERATE_V4(),
name TEXT NOT NULL UNIQUE
);
I want to create a function that takes a list of names and inserts multiple rows into the table, ignoring duplicate names, and returns an array of the IDs generated for the rows it inserted.
This works:
CREATE OR REPLACE FUNCTION insert_label(nms TEXT[])
RETURNS UUID[]
AS $$
DECLARE
ids UUID[];
BEGIN
CREATE TEMP TABLE tmp_names(name TEXT);
INSERT INTO tmp_names SELECT UNNEST(nms);
WITH new_names AS (
INSERT INTO label(name)
SELECT tn.name
FROM tmp_names tn
WHERE NOT EXISTS(SELECT 1 FROM label h WHERE h.name = tn.name)
RETURNING hid
)
SELECT ARRAY_AGG(hid) INTO ids
FROM new_names;
DROP TABLE tmp_names;
RETURN ids;
END;
$$ LANGUAGE PLPGSQL;
I have many tables with the exact same columns as the label table, so I would like to have a function that can insert into any of them. I'd like to create a dynamic query to do that. I tried that, but this does not work:
CREATE OR REPLACE FUNCTION insert_label(h_tbl REGCLASS, nms TEXT[])
RETURNS UUID[]
AS $$
DECLARE
ids UUID[];
query_str TEXT;
BEGIN
CREATE TEMP TABLE tmp_names(name TEXT);
INSERT INTO tmp_names SELECT UNNEST(nms);
query_str := FORMAT('WITH new_names AS ( INSERT INTO %1$I(name) SELECT tn.name FROM tmp_names tn WHERE NOT EXISTS(SELECT 1 FROM %1$I h WHERE h.name = tn.name) RETURNING hid)', h_tbl);
EXECUTE query_str;
SELECT ARRAY_AGG(hid) INTO ids FROM new_names;
DROP TABLE tmp_names;
RETURN ids;
END;
$$ LANGUAGE PLPGSQL;
This is the output I get when I run that function:
psql=# select insert_label('label', array['how', 'now', 'brown', 'cow']);
ERROR: syntax error at end of input
LINE 1: ...SELECT 1 FROM label h WHERE h.name = tn.name) RETURNING hid)
^
QUERY: WITH new_names AS ( INSERT INTO label(name) SELECT tn.name FROM tmp_names tn WHERE NOT EXISTS(SELECT 1 FROM label h WHERE h.name = tn.name) RETURNING hid)
CONTEXT: PL/pgSQL function insert_label(regclass,text[]) line 19 at EXECUTE
The query generated by the dynamic SQL looks like it should be exactly the same as the query from static SQL.
I got the function to work by changing the return value from an array of UUIDs to a table of UUIDs and not using CTE:
CREATE OR REPLACE FUNCTION insert_label(h_tbl REGCLASS, nms TEXT[])
RETURNS TABLE (hid UUID)
AS $$
DECLARE
query_str TEXT;
BEGIN
CREATE TEMP TABLE tmp_names(name TEXT);
INSERT INTO tmp_names SELECT UNNEST(nms);
query_str := FORMAT('INSERT INTO %1$I(name) SELECT tn.name FROM tmp_names tn WHERE NOT EXISTS(SELECT 1 FROM %1$I h WHERE h.name = tn.name) RETURNING hid', h_tbl);
RETURN QUERY EXECUTE query_str;
DROP TABLE tmp_names;
RETURN;
END;
$$ LANGUAGE PLPGSQL;
I don't know if one way is better than the other, returning an array of UUIDs or a table of UUIDs, but at least I got it to work one of those ways. Plus, possibly not using a CTE is more efficient, so it may be better to stick with the version that returns a table of UUIDs.
What I would like to know is why the dynamic query did not work when using a CTE. The query it produced looked like it should have worked.
If anyone can let me know what I did wrong, I would appreciate it.
... why the dynamic query did not work when using a CTE. The query it produced looked like it should have worked.
No, it was only the CTE without (required) outer query. (You had SELECT ARRAY_AGG(hid) INTO ids FROM new_names in the static version.)
There are more problems, but just use this query instead:
INSERT INTO label(name)
SELECT unnest(nms)
ON CONFLICT DO NOTHING
RETURNING hid;
label.name is defined UNIQUE NOT NULL, so this simple UPSERT can replace your function insert_label() completely.
It's much simpler and faster. It also defends against possible duplicates from within your input array that you didn't cover, yet. And it's safe under concurrent write load - as opposed to your original, which might run into race conditions. Related:
How to use RETURNING with ON CONFLICT in PostgreSQL?
I would just use the simple query and replace the table name.
But if you still want a dynamic function:
CREATE OR REPLACE FUNCTION insert_label(_tbl regclass, _nms text[])
RETURNS TABLE (hid uuid)
LANGUAGE plpgsql AS
$func$
BEGIN
RETURN QUERY EXECUTE format(
$$
INSERT INTO %s(name)
SELECT unnest($1)
ON CONFLICT DO NOTHING
RETURNING hid
$$, _tbl)
USING _nms;
END
$func$;
If you don't need an array as result, stick with the set (RETURNS TABLE ...). Simpler.
Pass values (_nms) to EXECUTE in a USING clause.
The tablename (_tbl) is type regclass, so the format specifier %I for format() would be wrong. Use %s instead. See:
Table name as a PostgreSQL function parameter
When creating stored procedure in redshift like below:
CREATE OR REPLACE PROCEDURE sp_test()
AS '
BEGIN
TRUNCATE TABLE TABLE_1;
INSERT INTO TABLE_1
SELECT COL1, COL2
FROM TABLE_2
WHERE CONDITION='SAMPLE';
END;
'
LANGUAGE plpgsql;
This gives an error syntax error near 'SAMPLE' because single quotes is already used for stored procedure begin and end. Also, here we would not be able to replace single quotes in INSERT query to double because redshift will consider it to be a column.
Few other posts suggests to use $$ for stored procedure, however $$ is not supported in sql workbench.
Any work around for this. Thanks.
Have you tried double-quoting the string?
WHERE CONDITION=''SAMPLE'';
Data Sample
CREATE TABLE t (id int, status text);
INSERT INTO t VALUES (42,'foo');
Procedure
CREATE OR REPLACE PROCEDURE sp_test()
AS'
BEGIN
TRUNCATE TABLE t;
INSERT INTO t
SELECT 8,''new record'';
END;'
LANGUAGE plpgsql;
Test procedure
CALL sp_test();
SELECT * FROM t
id | status
----+------------
8 | new record
(1 Zeile)
Here I have a question that I need to write a PL/SQL. The structure of the database is also linked. The question requires to use a sequence inside a procedure. I'm new to this and don't know if this works properly and my exec command doesn't seem working please help me out. Also is this how to look up the max shareholder_id that the sequence should start with, or can I a select inside create sequence?
Write a PL/SQL procedure called INSERT_DIRECT_HOLDER which will be used to insert new direct holders. Create a sequence to automatically generate shareholder_ids. Use this sequence in your procedure.
-Input parameters: first_name, last_name
DROP SEQUENCE shareholder_id_seq;
SELECT
MAX(shareholder_id)
FROM shareholder;
CREATE SEQUENCE shareholder_id_seq
INCREMENT BY 1
START WITH 25;
CREATE OR REPLACE PROCEDURE insert_direct_holder(
p_first_name in direct_holder.first_name%type,
p_last_name in direct_holder.last_name%type)
IS
v_shareholder_id NUMBER(6);
BEGIN
INSERT INTO DIRECT_HOLDER(direct_holder_id,first_name,last_name) values(shareholder_id_seq.nextval, p_first_name, p_last_name);
INSERT INTO shareholder (shareholder_id, type) VALUES (shareholder_id_seq.nextval,'Direct_Holder');
COMMIT;
END;
/
/* test command*/
exec insert_direct_holder( p_first_name, p_last_name );
You need to insert the record with same ID in both the tables.
also, you need to insert record into your parent table (shareholder) first and then child table(direct_holder).
CREATE OR REPLACE PROCEDURE insert_direct_holder(
p_first_name in direct_holder.first_name%type,
p_last_name in direct_holder.last_name%type)
IS
v_shareholder_id NUMBER(6);
BEGIN
v_shareholder_id := shareholder_id_seq.nextval;
INSERT INTO shareholder (shareholder_id, type) VALUES (v_shareholder_id,'Direct_Holder');
INSERT INTO DIRECT_HOLDER(direct_holder_id,first_name,last_name) values(v_shareholder_id, p_first_name, p_last_name);
COMMIT;
END;
/
/* test command*/
exec insert_direct_holder( p_first_name, p_last_name );
Sequence is created once to implement auto incrementing feature for any numeric column.
For the current use case it has to be created just once and left forever hopefully.Sequence can be modified in future if required.
If shareholder table has records in it already, then create the sequence with start value as SELECT MAX(shareholder_id) + 1 FROM shareholder; to avoid primary key constraint violation.
A slight modification is required for the stored procedure to use the same SHAREHOLDER.SHAREHOLDER_ID as the column has foreign key relationship with DIRECT_HOLDER.
Use INSERT ALL to insert to both the tables for the same sequence.nextval.
CREATE OR REPLACE PROCEDURE insert_direct_holder(
p_first_name in direct_holder.first_name%type,
p_last_name in direct_holder.last_name%type)
IS
BEGIN
INSERT ALL
INTO SHAREHOLDER
(shareholder_id, type) values(shareholder_id_seq.nextval,'Direct_Holder')
INTO DIRECT_HOLDER
(direct_holder_id,first_name,last_name) values
(shareholder_id_seq.nextval,p_first_name,p_last_name)
SELECT 'DUMMY' FROM dual;
COMMIT;
END;
/
dbfiddle demo with working code : https://dbfiddle.uk/?rdbms=oracle_18&fiddle=5d80488fb69d78d4b5087f06a5becf96
I am trying to make a TRIGGER that responds on an update at a table (appointments) which then calls a procedure (proc1()). The procedure needs to get arguments in order to insert a new row -based on those arguments- on a different table (medical_folder). Procedures can't have arguments, but after a bit of search I found that you can use a method like the following to kinda force your way though:
Passing arguments to a trigger function
With the above as my base I made the following UDF:
CREATE OR REPLACE FUNCTION AppointmentUpdate(docAMKA bigint, patAMKA bigint, dateNtime timestamp, conclusion varchar(500),cure2 varchar(500), drug_id integer)
RETURNS void AS $$
DECLARE
patAMKAv2 text;
drug_idv3 text;
BEGIN
patAMKAv2 := cast(AppointmentUpdate.patAMKA as text);
drug_idv3 := cast(AppointmentUpdate.drug_id as text);
DROP TRIGGER IF EXISTS tr1 on appointments;
CREATE TRIGGER tr1 BEFORE UPDATE ON appointments
EXECUTE PROCEDURE proc1(patAMKAv2,cure2,drug_idv3);
UPDATE appointments
SET diagnosis = conclusion
WHERE patientamka = patAMKA
AND doctoramka = docAMKA
AND t = dateNtime;
END;
$$ LANGUAGE plpgsql;
My procedure is as follows:
CREATE OR REPLACE FUNCTION proc1()
RETURNS trigger AS $$
declare
newid integer;
BEGIN
newid =((select max(medical_folder.id) from medical_folder)+1);
INSERT INTO medical_folder AS Medf(id,patient,cure,drug_id)
VALUES(newid,cast(TG_ARGV[0] as bigint),TG_ARGV[1],cast(TG_ARGV[2] as integer));
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
If I run it as is I am getting an error in proc1() here cast(TG_ARGV[0] as bigint) and it seems that in the UDF instead of sending the value of the arguments it sends the arguments themselves(if for example i do this EXECUTE PROCEDURE proc1(324,cure2,234); INSTEAD OF THIS EXECUTE PROCEDURE proc1(patAMKAv2,cure2,drug_idv3); ). Is there any way that you can force it to get the values instead?
P.S.:I now that this can be done a lot easier without the use of a TRIGGER and just make a UDF that does everything itself but unfortunately I have to do it using a TRIGGER.
P.S.2: I tried using function_name.variable_name instead of just var_name also tried using $1, $2, $3, ... , $n.
From the CREATE TRIGGER docs:
arguments
An optional comma-separated list of arguments to be provided to the function when the trigger is executed. The arguments are literal string constants. Simple names and numeric constants can be written here, too, but they will all be converted to strings.
http://rextester.com/OCA59277
You might be able to achieve what you are trying with dynamic SQL though (see EXECUTE). But I believe that you overcomplicate things. What you want to do is simply to get rows or IDs which participated in an UPDATE statement. PostgreSQL's DML statements (INSERT, UPDATE & DELETE) has a RETURNING clause just for that. Also, you can actually write more DML (sub-)statements within a single statement with writeable CTEs. Something like this should suffice:
WITH upd AS (
UPDATE appointments
SET diagnosis = conclusion
WHERE patientamka = patAMKA
AND doctoramka = docAMKA
AND t = dateNtime
RETURNING *
)
INSERT INTO medical_folder(patient, cure, drug_id)
SELECT patAMKAv2, cure2, drug_idv3
FROM upd;
Note: while writing this I realized that you actually don't use any of the fields from the UPDATE, but using FROM upd will ensure that as much rows will be inserted into medical_folder just as much appointments got updated. Which is what your original trigger-based logic did.
I recently found that RedShift supports CURSOR, and more specifically it supports the commands: DECLARE & FETCH.
I managed to create a cursor and fetch some of its rows but didn't find a way to:
Insert the fetched results into neither table or variable.
Iterate over the rows of the declared cursor in a dynamic fashion (based on while or any logical test)
I didn't find any documentation on Amazon on how to do that, does someone know if that is even possible? Thanks.
You can easily achieve this by creating a stored procedure which supports variables. You can read a dataset iterate through it and perform your logic.
The following example shows a procedure with output arguments. Arguments are input (IN), input and output (INOUT), and output (OUT).
CREATE OR REPLACE PROCEDURE test_sp2(f1 IN int,
f2 INOUT varchar(256), out_var OUT varchar(256))
AS $$
DECLARE
loop_var int;
BEGIN
IF f1 is null OR f2 is null THEN
RAISE EXCEPTION 'input cannot be null';
END IF;
DROP TABLE if exists my_etl;
CREATE TEMP TABLE my_etl(a int, b varchar);
FOR loop_var IN 1..f1 LOOP
insert into my_etl values (loop_var, f2);
f2 := f2 || '+' || f2;
END LOOP;
SELECT INTO out_var count(*) from my_etl;
END;
$$ LANGUAGE plpgsql;
call test_sp2(2,'2019');
f2 | column2
---------------------+---------
2019+2019+2019+2019 | 2
(1 row)
source - https://docs.aws.amazon.com/redshift/latest/dg/stored-procedure-create.html
Redshift doesn't have variables. Inserting into another table easier and much faster with INSERT INTO ... SELECT.
If I understand your second use case, I don't know of any relational database which supports that behaviour. You can filter the cursor when you create it, but once it is created your options are getting the next row or closing the cursor. If you need to filter then you can DECLARE a new cursor.