https://github.com/thujuli/car-dealer-db
A simple database design for used car dealers
https://github.com/thujuli/car-dealer-db
Last synced: about 1 year ago
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A simple database design for used car dealers
- Host: GitHub
- URL: https://github.com/thujuli/car-dealer-db
- Owner: thujuli
- Created: 2023-07-18T05:36:15.000Z (almost 3 years ago)
- Default Branch: main
- Last Pushed: 2023-07-23T13:35:42.000Z (almost 3 years ago)
- Last Synced: 2025-02-01T19:23:40.483Z (over 1 year ago)
- Language: Python
- Homepage:
- Size: 222 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# DATABASE DESIGN FOR USED CAR DEALERS
## Backgound
This my final project for RDMS using PostgreSQL.....
## Objective
- Create database design for used car dealers
- Implement database design to database server
- Create and input dummy data for each table
- Test Backup and restore database
- Creating Transactional Query and Analytical Query
## Requirements
- PostgreSQL
- PostgreSQL Client (psql, DBeaver, pgAdmin etc)
- Python3
## Create Database Design
### Entities and Attributes
### Relations
- One City can have many Users (Sellers and Buyers)
- One Seller can own many Cars
- One Car can have many Ads
- One Buyer can bid many Ads
- One Advertisment offered be many Buyers
### Table Structure and Relations
### Business Rules
#### Cities
- All fields cannot be empty
#### Sellers
- Primary key auto increment
- All fields cannot be empty
- Phone number cannot be the same (unique)
#### Buyers
- Primary key auto increment
- All fields cannot be empty
- Phone number cannot be the same (unique)
#### Cars
- Primary key auto increment
- All fields cannot be empty
- Price must be greater than 0
#### Ads
- Primary key auto increment
- All fields cannot be empty
- Default date is current date
#### Bids
- Primary key auto increment
- All fields cannot be empty
- Price must be greater than 0
- Default date is current date
- Status must be sent or cancel
- Default status is sent
## Setup Project
#### Clone this repository
```bash
# clone using ssh
git clone git@github.com:thujuli/car-dealer-db.git
# clone using https
git clone https://github.com/thujuli/car-dealer-db.git
```
#### Change directory to this repository
```bash
cd car-dealer-db/
```
## Implementation To The Database Server
#### Create new database using psql
```bash
psql --username=postgres --command="CREATE DATABASE car_dealer;" --password
```
#### Create all tables from sql script
```bash
psql --username=postgres --dbname=car_dealer --password --file=sql/ddl.sql
```
#### Checks all tables already exists
```bash
psql --username=postgres --dbname=car_dealer --command="\dt" --password
```
## Create And Input Dummy Data For Each Table
#### Create virtual environment
```bash
python -m venv .venv
```
#### Use the virtual environment
```bash
source .venv/bin/activate
```
#### Install third party packages from requirements.txt
```bash
pip install -r requirements.txt
```
#### Change directory to dataset
```bash
cd dataset/
```
#### Run python script
```bash
python main.py
```
#### Checks all created csv files
```bash
ls final/
```
#### Import csv files (dummy data) for each table
```bash
# import for table cities
psql --username=postgres --dbname=car_dealer --command="\copy cities from 'final/cities.csv' delimiter ',' csv header" --password
# import for table sellers
psql --username=postgres --dbname=car_dealer --command="\copy sellers from 'final/sellers.csv' delimiter ',' csv header" --password
# import for table buyers
psql --username=postgres --dbname=car_dealer --command="\copy buyers from 'final/buyers.csv' delimiter ',' csv header" --password
# import for table cars
psql --username=postgres --dbname=car_dealer --command="\copy cars from 'final/cars.csv' delimiter ',' csv header" --password
# import for table ads
psql --username=postgres --dbname=car_dealer --command="\copy ads from 'final/ads.csv' delimiter ',' csv header" --password
# import for table bids
psql --username=postgres --dbname=car_dealer --command="\copy bids from 'final/bids.csv' delimiter ',' csv header" --password
```
#### Test queries to each table
```bash
# queries table cities
psql --username=postgres --dbname=car_dealer --command="select * from cities;" --password
# queries table sellers
psql --username=postgres --dbname=car_dealer --command="select * from sellers;" --password
# queries table buyers
psql --username=postgres --dbname=car_dealer --command="select * from buyers;" --password
# queries table cars
psql --username=postgres --dbname=car_dealer --command="select * from cars;" --password
# queries table ads
psql --username=postgres --dbname=car_dealer --command="select * from ads;" --password
# queries table bids
psql --username=postgres --dbname=car_dealer --command="select * from bids;" --password
```
#### Back to main directory
```bash
cd ..
```
## Backup And Restore Database
#### Backup database using pg_dump
```bash
pg_dump --username=postgres --dbname=car_dealer --password > backup/db.sql
```
#### Create a new database to restore the database
```bash
psql --username=postgres --command="CREATE DATABASE restore_car_dealer;" --password
```
#### Restore database using psql
```bash
pg_dump --username=postgres --dbname=restore_car_dealer --file=backup/db.sql --password > backup/db.sql
```
#### Test queries to each table
```bash
# queries table cities
psql --username=postgres --dbname=restore_car_dealer --command="select * from cities;" --password
# queries table sellers
psql --username=postgres --dbname=restore_car_dealer --command="select * from sellers;" --password
# queries table buyers
psql --username=postgres --dbname=restore_car_dealer --command="select * from buyers;" --password
# queries table cars
psql --username=postgres --dbname=restore_car_dealer --command="select * from cars;" --password
# queries table ads
psql --username=postgres --dbname=restore_car_dealer --command="select * from ads;" --password
# queries table bids
psql --username=postgres --dbname=restore_car_dealer --command="select * from bids;" --password
```
## Transactional Query
#### Look for cars with a production date greater than 2015
```sql
SELECT * FROM cars
WHERE "year" > 2015;
```
#### Add one new record to the Bids Table
```sql
/* insert record */
INSERT INTO bids (id, buyer_id, ad_id, price, status)
VALUES (101, 3, 25,350000000, 'sent' );
/* query select */
SELECT * FROM bids;
```
#### Find all cars owned by one user and sort by newest
```sql
/* example, seller name is 'Damu Samosir' */
SELECT c.id AS card_id, c.brand, c.model, c.year, c.price, a.date
FROM cars AS c
JOIN sellers AS s ON c.seller_id = s.id
JOIN ads AS a ON c.id = a.car_id
WHERE s.name = 'Damu Samosir'
ORDER BY a.date DESC;
```
#### Find all cars by model name and sort by low price
```sql
/*example model name is 'yaris'*/
SELECT *
FROM cars
WHERE model ILIKE '%yaris%'
ORDER BY price ASC;
```