Data Modeling with Postgres

---

Sparkify, a startup, wants to analyze the data they've been collecting on songs and user activity on their new music streaming app. Their data is in a directory of JSON logs on user activity on the app and another directory with JSON metadata on the songs in their app. The goal of this project is to create a Postgres databsae that allow analytics team to optimize queries on song play analysis.

Data Modeling Structure

---

The database structure uses Star Schema with following tables:

Fact Table

1. songplay: records in log data associated with song plays i.e. records with page NextSong

• songplay_id, start_time, user_id, level, song_id, artist_id, session_id, location, user_agent

Dimension Tables

2. users: users in the app

• song_id, title, artist_id, year, duration

3. artists: artists in music database

• artist_id, name, location, latitude, longitude

4. time: timestamps of records in songplay broken down into specific units

• start_time, hour, day, week, month, year, weekday

How to Run

---

1. run create_tables.py
2. run etl.py

Files

---

1. test.ipynb displays the first few rows of each table.

2. create_tables.py drops and creates tables.

3. etl.ipynb reads and processes a single file from song_data and log_data and loads the data into tables. This notebook contains detailed instructions on the ETL process for each of the tables.

4. etl.py reads and processes files from song_data and log_data and loads them into tables.

5. sql_queries.py contains all sql queries, and is imported into the last three files above.