I want to use PostgreSQL's declarative table partitioning on a column with UUID values. I want it partitioned by values that are returned by a SELECT.
CREATE TABLE foo (
id uuid NOT NULL,
type_id uuid NOT NULL,
-- other columns
PRIMARY KEY (id, type_id)
) PARTITION BY LIST (type_id);
CREATE TABLE foo_1 PARTITION OF foo
FOR VALUES IN (SELECT id FROM type_ids WHERE type_name = 'type1');
CREATE TABLE foo_2 PARTITION OF foo
FOR VALUES IN (SELECT id FROM type_ids WHERE type_name = 'type2');
I don't want to use specific UUIDs in FOR VALUES IN ('uuid'), since the UUIDs may differ by environment (dev, qa, prod). However, the SELECT syntax doesn't seem to be accepted by Postgres. Any suggestions?
I just wanted the SELECT to be evaluated at the table creation time
You should have made that clear in the question, not in a comment.
In that case - if this is a one time thing, you can use dynamic SQL, e.g. wrapped into a procedure
create procedure create_partition(p_part_name text, p_type_name text)
as
$$
declare
l_sql text;
l_id uuid;
begin
select id
into l_id
from type_ids
where type_name = p_type_name;
l_sql := format('CREATE TABLE %I PARTITION OF foo FOR VALUES IN (%L)', p_part_name, l_id);
execute l_sql;
end;
$$
language plpgsql;
Then you can do:
call create_partition('foo_1', 'type1');
call create_partition('foo_2', 'type2');
Related
I'd like to run the create_company_maybe_race_condition() function below, but think it might create a race condition if plpgsql functions don't run sequentially. I'm on Postgres 12.
My real world scenario is that I have Row Level Security turned on for all of my tables. The RLS check relies on an access control list in a permissions table. When I add a row to a table, I can't use the RETURNING clause since there isn't a row in the permissions table yet that'll allow the user to read the object.
CREATE TABLE companies (
PRIMARY KEY(company_id),
company_id uuid,
);
CREATE TABLE departments (
PRIMARY KEY (department_id),
department_id uuid DEFAULT gen_random_uuid(),
name text,
company_id uuid REFERENCES companies
);
/**********/
CREATE FUNCTION create_company_maybe_race_condition ()
RETURNS void AS $$
DECLARE
v_company_id := gen_random_uuid();
BEGIN
INSERT INTO companies (company_id)
VALUES (v_company_id);
INSERT INTO departments (company_id, name)
VALUES (v_company_id, 'My Department'); -- Postgres doesn't know that it depends on companies
END;
$$ LANGUAGE plpgsql;
/**********/
CREATE FUNCTION create_company_no_race_condition ()
RETURNS void AS $$
DECLARE
v_company_id uuid;
BEGIN
INSERT INTO companies (company_id)
VALUES (DEFAULT)
RETURN company_id INTO v_company_id;
INSERT INTO departments (company_id, name)
VALUES (v_company_id, 'My Department');
END;
$$ LANGUAGE plpgsql;
I am very new to Postgres SQL. My requirement is to pass a dynamic number of columnId, columnValue pair and insert this combination in a table(Example: employeeId, employeeName combination). The length of list can be anything. I am thinking of building dynamic query at the code-side and pass it as string to function and execute the statement. Is there any better approach for this problem. Any example or idea will be much appreciated.
If you are allowed to pass that information as a structured JSON value, this gets quite easy. Postgres has a feature to map a JSON value to a table type using the function json_populate_record
Sample table:
create table some_table
(
id integer primary key,
some_name text,
some_date date,
some_number integer
);
The insert function:
create function do_insert(p_data text)
returns void
as
$$
insert into some_table (id, some_name, some_date, some_number)
select (json_populate_record(null::some_table, p_data::json)).*;
$$
language sql;
Then you can use:
select do_insert('{"id": 42, "some_name": "Arthur"}');
select do_insert('{"id": 1, "some_value": 42}');
Note that columns that are not part of the passed JSON string are explicitly set to NULL using this approach.
If the passed string contains column names that do not exist, they are simply ignored, so
select do_insert('{"id": 12, "some_name": "Arthur", "not_there": 123}');
will ignore the not_there "column".
Online example: https://rextester.com/JNIBL25827
Edit
A similar approach can be used for updating:
create function do_update(p_data text)
returns void
as
$$
update some_table
set id = t.id,
some_name = t.some_name,
some_date = t.some_date,
some_number = t.some_number
from json_populate_record(null::some_table, p_data::json) as t;
$$
language sql;
or using insert on conflict to cover both use cases with one function:
create function do_upsert(p_data text)
returns void
as
$$
insert into some_table (id, some_name, some_date, some_number)
select (json_populate_record(null::some_table, p_data::json)).*
on conflict (id) do update
set id = excluded.id,
some_name = excluded.some_name,
some_date = excluded.some_date,
some_number = excluded.some_number
$$
language sql;
I have a job table. I have an industries table. Jobs and industries have a many to many relationship via a join table called industriesjobs. Both tables have uuid is their primary key. My question is two fold. Firstly is it feasible to write two functions to insert data like this? If this is feasible then my second question is how do I express an array of the uuid column type. I'm unsure of the syntax.
CREATE OR REPLACE FUNCTION linkJobToIndustries(jobId uuid, industiresId uuid[]) RETURNS void AS $$
DECLARE
industryId uuid[];
BEGIN
FOREACH industryId SLICE 1 IN ARRAY industriesId LOOP
INSERT INTO industriesjobs (industry_id, job_id) VALUES (industryId, jobId);
END LOOP;
RETURN;
END;
$$ LANGUAGE plpgsql;
CREATE OR REPLACE FUNCTION insertJobWithIndistries(orginsation varchar, title varchar, addressId uuid, industryIds uuid[]) RETURNS uuid AS $$
DECLARE
jobId uuid;
BEGIN
INSERT INTO jobs ("organisation", "title", "address_id") VALUES (orginsation, title, addressId) RETURNING id INTO jobId;
SELECT JobbaLinkJobToIndustries(jobId, industryIds);
END;
$$ LANGUAGE plpgsql;
SELECT jobId FROM insertJobWithIndistries(
'Acme Inc'::varchar,
'Bomb Tester'::varchar,
'0030cfb3-1a03-4c5a-9afa-6b69376abe2e',
{ 19c2e0ee-acd5-48b2-9fac-077ad4d49b19, 21f8ffb7-e155-4c8f-acf0-9e991325784, 28c18acd-99ba-46ac-a2dc-59ce952eecf2 }
);
Thanks in advance.
Key to a solution are the function unnest() to (per documentation):
expand an array to a set of rows
And a data-modifying CTE.
A simple query does the job:
WITH ins_job AS (
INSERT INTO jobs (organisation, title, address_id)
SELECT 'Acme Inc', 'Bomb Tester', '0030cfb3-1a03-4c5a-9afa-6b69376abe2e' -- job-data here
RETURNING id
)
INSERT INTO industriesjobs (industry_id, job_id)
SELECT indid, id
FROM ins_job i -- that's a single row, so a CROSS JOIN is OK
, unnest('{19c2e0ee-acd5-48b2-9fac-077ad4d49b19
, 21f8ffb7-e155-4c8f-acf0-9e9913257845
, 28c18acd-99ba-46ac-a2dc-59ce952eecf2}'::uuid[]) indid; -- industry IDs here
Also demonstrating proper syntax for an array of uuid. (White space between elements and separators is irrelevant while not inside double-quotes.)
One of your UUIDs was one character short:
21f8ffb7-e155-4c8f-acf0-9e991325784
Must be something like:
21f8ffb7-e155-4c8f-acf0-9e9913257845 -- one more character
If you need functions, you do that, too:
CREATE OR REPLACE FUNCTION link_job_to_industries(_jobid uuid, _indids uuid[])
RETURNS void AS
$func$
INSERT INTO industriesjobs (industry_id, job_id)
SELECT _indid, _jobid
FROM unnest(_indids) _indid;
$func$ LANGUAGE sql;
Etc.
Related:
Insert data in 3 tables at a time using Postgres
How to insert multiple rows using a function in PostgreSQL
We are looking to convert our database over to Postgres (9.3.5), which I have no experience with, and I am trying to get our audit tables up and running. I understand that each table will need its own trigger, but all triggers can call a single function.
The trigger on the table is passing a list of the columns that need to be audited since some of our columns are not tracked.
Here are some of the posts I followed:
- https://stackoverflow.com/a/7915100/229897
- http://www.postgresql.org/docs/9.3/static/plpgsql-statements.html
- http://www.postgresql.org/docs/9.4/static/plpgsql-trigger.html
When I run this I get the error: ERROR: syntax error at or near "$1"
DROP TABLE IF EXISTS people;
DROP TABLE IF EXISTS a_people;
CREATE TABLE IF NOT EXISTS people (
record_id SERIAL PRIMARY KEY NOT NULL,
first_name VARCHAR NOT NULL,
last_name VARCHAR NOT NULL,
last_updated_on TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);
CREATE TABLE IF NOT EXISTS a_people (
record_id SERIAL PRIMARY KEY NOT NULL,
a_record_id INT,
first_name VARCHAR NULL,
last_name VARCHAR NULL,
last_updated_on TIMESTAMP
);
/******************************************************/
--the function
CREATE OR REPLACE FUNCTION audit_func()
RETURNS TRIGGER AS
$BODY$
DECLARE
audit TEXT := TG_TABLE_SCHEMA || '.a_' || TG_TABLE_NAME;
cols TEXT := TG_ARGV[0];
BEGIN
EXECUTE format('INSERT INTO %1$s(a_%2$s) SELECT %2$s FROM ($1)', audit, cols) USING OLD;
NEW.last_updated_on = CURRENT_TIMESTAMP;
RETURN NEW;
END;
$BODY$
LANGUAGE plpgsql;
/******************************************************/
--the trigger calling the function to update inbound records
CREATE TRIGGER build_user_full_name_trg
BEFORE UPDATE
ON people
FOR EACH ROW WHEN (OLD.* IS DISTINCT FROM NEW.*)
EXECUTE PROCEDURE audit_func('record_id,first_name,last_name');
/******************************************************/
INSERT INTO people (first_name, last_name) VALUES ('George','Lincoln');
UPDATE people SET last_name = 'Washington' WHERE first_name = 'George';
SELECT * FROM people;
I welcome your assistance (and patience)!
This subselect should work:
EXECUTE format('INSERT INTO %1$s(a_%2$s) SELECT %2$s FROM (select ($1).*) XX', audit, cols) USING OLD;
Consider the postgres view which joins together two tables table_geom and table_data by the field id_data (id_data being the primary key of table_data and a foreign key in table_geom):
CREATE OR REPLACE VIEW myschema.view AS
SELECT table_geom.geom, table_geom.id_geom, table_geom.id_data,
table_data.id_data, table_data.data
FROM myschema.table_geom, myschema.table_data
WHERE table_geom.id_data = table_data.id_data;
id_geom and id_data are UUIDs. I'd like to autogenerate them on insert using uuid_generate_v4() with a rule such as
CREATE OR REPLACE RULE view_insert_rule AS
ON INSERT TO myschema.view DO INSTEAD (
INSERT INTO myschema.table_geom (geom, id_geom, id_data) VALUES (new.geom, (select uuid_generate_v4()), $ID_DATA$);
INSERT INTO myschema.table_data (id_data, data) VALUES ($ID_DATA$, new.data);
);
Problem: $ID_DATA$ needs to be the same UUID when inserting into the two tables.
One attempt was
CREATE OR REPLACE RULE view_insert_rule AS
ON INSERT TO myschema.view DO INSTEAD (
WITH ins_data as (
INSERT INTO myschema.table_data (id_data, data) VALUES ((select uuid_generate_v4()), new.data) RETURNING id_data
)
INSERT INTO myschema.table_geom (geom, id_geom, id_data) VALUES (new.geom, (select uuid_generate_v4()), ins_data.id_data);
);
which however does not work due to ERROR: cannot refer to NEW within WITH query.
Any idea how write such an insert rule?
Since you are doing an INSERT on a view, the recommended procedure is an INSTEAD OF INSERT trigger on the view. In the trigger function you rewrite the insert on the view into two inserts on the underlying tables:
CREATE FUNCTION insert_new_uuids() RETURNS trigger AS $$
DECLARE
new_id uuid;
BEGIN
new_id := uuid_generate_v4();
INSERT INTO myschema.table_data (id_data, data) VALUES (new_id, NEW.data);
INSERT INTO myschema.table_geom (geom, id_geom, id_data) VALUES (NEW.geom, uuid_generate_v4(), new_id);
RETURN NEW;
END;
$$ LANGUAGE plpgsql;
CREATE TRIGGER ins_view
INSTEAD OF INSERT ON myschema."view"
FOR EACH ROW EXECUTE PROCEDURE insert_new_uuids();