Theo's Typesafe Cult•4mo ago

help with DB schema

Hi, I need help with designing a database, I'm fairly new to SQL (postgres) and I'm terrified of over-engineering. Essentially, I'm building an app for an organization that has dozen of workplaces, each consisting of a team of therapists with the following requirements: - Each workplace/location needs a weekly schedule, which therapist in which room, and with which client. - they don't need a yearly calendar. - No one-off events/sessions. There are usually between 4-6 therapists and 8-9 clients. My thoughts: Create a table

events

events

with columns:

create table events (
id SERIAL primary KEY,
title text,
day text,
start_time time(0),
end_time time(0)
);

create table events (
id SERIAL primary KEY,
title text,
day text,
start_time time(0),
end_time time(0)
);

and another table with

participants

participants

with cols:

  id ...,
  event_id INTEGER references events (id),
  participant_id INT,
  participant_type, -- 'user/therapist' or 'client'
  FOREIGN KEY (participant_id) REFERENCES clients (id) DEFERRABLE INITIALLY DEFERRED, -- ChatGPT's suggestion to make a column refer one of TWO tables (clients/users)
  FOREIGN KEY (participant_id) REFERENCES users (id) DEFERRABLE INITIALLY DEFERRED

  id ...,
  event_id INTEGER references events (id),
  participant_id INT,
  participant_type, -- 'user/therapist' or 'client'
  FOREIGN KEY (participant_id) REFERENCES clients (id) DEFERRABLE INITIALLY DEFERRED, -- ChatGPT's suggestion to make a column refer one of TWO tables (clients/users)
  FOREIGN KEY (participant_id) REFERENCES users (id) DEFERRABLE INITIALLY DEFERRED

I'm unfamiliar with SQL and don't know how many tables is too many for a small application, so I'm afraid of committing horrible design mistakes now. Is this a good approach to the problem? A 'stupid' alternative is to shove everything in the events table. I'm not sure how, use an array of IDs in a "participants" column? I read everywhere that using arrays is dangerous in DB, idk why.

1 Reply

ImEgg•4mo ago

https://www.studytonight.com/dbms/database-normalization.php I would say if you can get your database to be at the 3rd Form of normalization, you'll be just fine. "over-engineering" is a pretty weird term to use. I'd try to focus more on best-practices and why normalization is important and other basics of SQL database design. Tons of resources online to learn.

Normalization in DBMS - 1NF, 2NF, 3NF, BCNF, 4NF and 5NF | Studyton...

Learn Normalization in DBMS and how to implement 1NF in DBMS, 2NF in DBMS, BCNF in DBMS, 4NF in DBMS, and 5NF in DBMS with examples.

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help with DB schema