https://github.com/valentinocarmonas/universe
A project done in psql for freecodecamp.org
https://github.com/valentinocarmonas/universe
Last synced: 5 months ago
JSON representation
A project done in psql for freecodecamp.org
- Host: GitHub
- URL: https://github.com/valentinocarmonas/universe
- Owner: ValentinoCarmonaS
- License: mit
- Created: 2025-02-25T02:47:28.000Z (8 months ago)
- Default Branch: main
- Last Pushed: 2025-03-06T20:20:25.000Z (7 months ago)
- Last Synced: 2025-03-06T21:19:28.468Z (7 months ago)
- Homepage:
- Size: 12.7 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Universe Database Project
*A PostgreSQL database modeling celestial objects for freeCodeCamp.org*
This project involves creating a structured relational database named `universe` to catalog galaxies, stars, planets, moons, and cosmic events. The database adheres to strict naming conventions, data type usage, and relational integrity, demonstrating proficiency in SQL and database design.
---
## **Project Overview**
The `universe` database organizes celestial data into interconnected tables, enabling queries about cosmic relationships and events. Key features include:
- **5 Tables**: `galaxy`, `star`, `planet`, `moon`, and `space_events` (additional table for astronomical phenomena).
- **Relational Structure**: Hierarchical foreign key relationships (e.g., stars belong to galaxies, planets orbit stars).
- **Data Integrity**: Constraints like `UNIQUE`, `NOT NULL`, and `BOOLEAN` flags enforce valid data.
- **Scalability**: Auto-incrementing primary keys (`galaxy_id`, `star_id`, etc.) and flexible schema design.
---
## **Database Schema**
### **Tables & Relationships**
| Table | Columns (Key Examples) | Relationships |
|----------------|---------------------------------------------------------------------------------------|--------------------------------------------|
| `galaxy` | `galaxy_id` (PK), `name` (UNIQUE), `age_in_millions_of_years` (INT), `description` (TEXT) | Linked to `star` via `galaxy_id` (FK) |
| `star` | `star_id` (PK), `galaxy_id` (FK), `age_in_millions_of_years` (INT) | Parent of `planet` |
| `planet` | `planet_id` (PK), `star_id` (FK), `has_life` (BOOLEAN), `can_have_life` (BOOLEAN) | Parent of `moon` |
| `moon` | `moon_id` (PK), `planet_id` (FK), `mass_in_kg` (NUMERIC) | Child of `planet` |
| `space_events` | `space_events_id` (PK), `event_type` (VARCHAR), `planet_id` (FK), `date` (DATE) | Optional links to `planet`, `star`, `moon` |
### **Key Constraints**
- **Primary Keys**: All tables use `_id` (e.g., `moon_id`).
- **Foreign Keys**: Ensure referential integrity (e.g., `star.galaxy_id` references `galaxy.galaxy_id`).
- **Uniqueness**: `name` columns in `galaxy`, `star`, `planet`, and `moon` are unique.
- **Data Types**:
- `NUMERIC` for precise values (e.g., moon mass).
- `BOOLEAN` for flags like `has_life`.
- `TEXT` for descriptions.
---
## **Setup & Usage**
### **Restore the Database**
1. Download the `universe.sql` file.
2. Run:
```bash
psql -U [username] -d postgres -f universe.sql
```
### **Example Queries**
1. Find all moons orbiting planets with potential life:
```sql
SELECT m.name, p.name AS planet
FROM moon m
JOIN planet p ON m.planet_id = p.planet_id
WHERE p.can_have_life = TRUE;
```
2. List stars in the "Andromeda" galaxy:
```sql
SELECT s.name, s.age_in_millions_of_years
FROM star s
JOIN galaxy g ON s.galaxy_id = g.galaxy_id
WHERE g.name = 'Andromeda';
```
---
## **Technologies Used**
- **PostgreSQL**: Database management.
- **SQL**: Schema design, constraints, and queries.
- **pg_dump**: Database backup/restore.
---
This project demonstrates a strong grasp of relational database principles, including normalization, constraints, and hierarchical relationships. The inclusion of an additional `space_events` table highlights creativity in extending functionality beyond core requirements.
A project completed as part of the freeCodeCamp.org Relational Database Certification.