how to prepare a create table statement

po 4. 1. 2021 v 11:31 odesílatel Alexander Mills <
alexander.d.mills@gmail.com> napsal:

I am trying to create 500 partitions using a loop:

do $$
declare
counter integer := 0;
begin
while counter <= 500 loop
PREPARE create_table(int) AS
CREATE TABLE mbk_auth_method_$1 PARTITION OF mbk_auth_method FOR VALUES WITH (modulus 500, remainder $1);
EXECUTE create_table (counter);
counter := counter + 1;
end loop;
end$$;

problem is that a CREATE TABLE cannot be prepared statement..

Anyone know how I can accomplish the above? Seems like this is a missing
feature - to prepare a CREATE TABLE statement..

This is a bad idea. You should not use PREPARE statement in plpgsql code
ever. Your code looks like from MySQL :)

do $$
begin
for i in 0..500
loop
execute format('CREATE TABLE %I PARTITION OF mbk_auth_method FOR VALUES
WITH (modulus 500, remainder %s)',
'mbk_auth_method_' || i, i);
end loop;
end;
$$;

It can be a little bit messy, but EXECUTE from the plpgsql environment is a
different statement than EXECUTE from SQL environment. Dynamic statements
are "prepared" implicitly in plpgsql. You cannot use PREPARE there.

Regards

Pavel

On Sun, Jan 03, 2021 at 08:46:19PM -0800, Alexander Mills wrote:

I am trying to create 500 partitions using a loop:

do $$
declare
counter integer := 0;
begin
while counter <= 500 loop
PREPARE create_table(int) AS
CREATE TABLE mbk_auth_method_$1 PARTITION OF mbk_auth_method FOR
VALUES WITH (modulus 500, remainder $1);
EXECUTE create_table (counter);
counter := counter + 1;
end loop;
end$$;

Anyone know how I can accomplish the above? Seems like this is a missing
feature - to prepare a CREATE TABLE statement..

What if you simply used a FOR loop and EXECUTE with format()? Say,
roughly, something like that:
FOR i IN 1..num_tables LOOP
EXECUTE format('
CREATE TABLE mbk_auth_method_%I PARTITION OF mbk_auth_method FOR
VALUES WITH (modulus 500, remainder %I)', i, i);
END LOOP;
--
Michael