Adding an Array of INT column where each value is a primary key from another table

Question

Given two tables like so

CREATE TABLE participants(
    id SERIAL PRIMARY KEY,
    Name TEXT NOT NULL,
    Title TEXT NOT NULL
);

CREATE TABLE meetings (
    id SERIAL PRIMARY KEY,
    Organizer TEXT NOT NULL,
    StartTime DATE NOT NULL,
    EndTime DATE NOT NULL,
    Participants INT[],
);

I want Participants column of 'meetings' table to contain set of integers which are all primary keys (specific participant) from 'participants' table.

How do I define this field in 'meetings' table ?

Answer 1

The old fashioned way is to create a many-many table, with a couple of commonsense constraints:

CREATE TABLE meetings_participants(
    meeting_id int not null,
    participant_id int not null,
    primary key (meeting_id, participant_id),
    foreign key(meeting_id) references meetings(id),
    foreign key(participant_id) references participants(id)
)

Now it is easy to add and remove people to meetings be inserting or deleting rows or query meetings that e.g. have 4 or more participants.