Postgresql function to create table with dynamic table name? - postgresql

Question

Let's say I have several users, each with their own set of contacts. Users get to select which 3rd parties have access to their contacts.
I could maybe create 1 large contact table and have an 'owner' column so that I can identify which contacts belong to which users. However, I'd then need to maintain row-level permissions so that I can restrict which 3rd parties do/don't have access to specific user contacts.
Instead, I think (and I could be mistaken here) it makes more sense to have a contact table for each user, e.g.: contact_e878df81_eba1_4a61_b592_30ac7100362a. I could then manage permissions in a separate table.
To create these 'dynamic contact tables', I have the following function:
CREATE OR REPLACE FUNCTION create_contact_table(IN tbl_name text) RETURNS INT AS $$
DECLARE
table_name text;
BEGIN
table_name = tbl_name;
create table IF NOT EXISTS table_name
(
id serial not null
constraint test_pkey
primary key,
firstname varchar not null,
lastname varchar not null,
age int not null,
address varchar not null,
email varchar not null,
created timestamp default CURRENT_TIMESTAMP
);
alter table table_name
owner to postgres;
RETURN 1;
END ;
$$ LANGUAGE plpgsql;
When I execute the function (create_contact_table(contact_e878df81_eba1_4a61_b592_30ac7100362a), the table is created, but the name of the table is table_name...
Why is that? How can I fix it so that the table name is correct?

Answer 1

You can do it only using dynamic SQL, for example:
CREATE OR REPLACE FUNCTION create_contact_table(tbl_name text)
RETURNS boolean
LANGUAGE plpgsql
AS $function$
declare
v_sql text;
t1 text;
begin
v_sql = '
create table %I
(
id serial not null
constraint test_pkey
primary key,
firstname varchar not null,
lastname varchar not null,
age int not null,
address varchar not null,
email varchar not null,
created timestamp default CURRENT_TIMESTAMP
);
';
raise notice 'SQL:: %', v_sql;
EXECUTE format(v_sql, tbl_name);
return true;
END;
$function$
;