PostgreSQL insert into and select from an array of user defined objects - sql

Question

I've been having some issues while trying to learn PostgreSQL. I've created a relational object called person and then a table consisting of a primary integer key and an array of person objects. I have a feeling it's the way I am inserting rows into this array however, I am unsure of how to access specific columns of the object as well (Ex. person.name).
Currently the only way I was able to insert a row is as follows however, I think it may just be making a string object instead of the proper person object.
INSERT INTO towns VALUES (0, '{"(bob,blue,springfield,33)"}');
For reference the schema I created is:
CREATE TYPE person AS (
name text,
favorite_color text,
hometown text,
age integer
);
CREATE TABLE towns (
town_id integer PRIMARY KEY,
people person[]
);

Answer 1

That's one of the reasons I prefer the array[...] syntax over '{...}'. You don't need to think about nesting quotes:
INSERT INTO towns (town_id, people)
VALUES
(0, array[('bob','blue','springfield',33)::person]);
('bob','blue','springfield',33)::person creates a record of type person and array[...] that makes that a single element array. You have to cast the anonymous record created with (...) to person to make this work. If you want to insert multiple person records into the array it's a bit less typing to case the whole array at the end:
array[('bob','blue','springfield',33), ('arthur','red','sleepytown',42)]::person[]
To select a specific element of a record in an array, you can use e.g:
select town_id, people[1].name
from towns

Answer 2

You are combining 2 things here, a field type as array of a composite type person.
To insert a composite type you should do something like this ROW("bob","blue","springfield",33), note that ROW keyword is optional
For array types you should use brackets inside single quotes, like '{val1,val2}', in your case, you are adding only one element of the array, which result is a person type.
Your example should look like:
INSERT INTO towns VALUES (0, '{ROW("bob","blue","springfield",33)}');
Note that the double quotes are for values inside the person type, not for the whole object.
References: Composite Types, Arrays
To access the person value, you have to wrap the object in (), so (person).name

Answer 3

The only way I could get this to work was by inserting in the following way:
INSERT INTO towns VALUES (0, (array[ROW('bob','blue','springfield',33)::person]));
And to select you would have to do this:
select (people[1]).age from towns;