sql_queries.py

# DROP TABLES

songplay_table_drop = """DROP TABLE IF EXISTS songplays"""
user_table_drop = """DROP TABLE IF EXISTS users"""
song_table_drop = """DROP TABLE IF EXISTS songs"""
artist_table_drop = """DROP TABLE IF EXISTS artists"""
time_table_drop = """DROP TABLE IF EXISTS time"""

# CREATE TABLES

user_table_create = ("""
    CREATE TABLE IF NOT EXISTS users (
        user_id INT PRIMARY KEY,
        first_name VARCHAR NOT NULL,
        last_name VARCHAR NOT NULL,
        gender VARCHAR,
        level VARCHAR
    );
""")

song_table_create = ("""
    CREATE TABLE IF NOT EXISTS songs (
        song_id VARCHAR PRIMARY KEY,
        title VARCHAR NOT NULL,
        artist_id VARCHAR,
        year INT,
        duration FLOAT
    );
""")

artist_table_create = ("""
    CREATE TABLE IF NOT EXISTS artists (
        artist_id VARCHAR PRIMARY KEY,
        name VARCHAR NOT NULL,
        location VARCHAR,
        latitude VARCHAR,
        longitude VARCHAR
    );
""")

time_table_create = ("""
    CREATE TABLE IF NOT EXISTS time (
        start_time TIMESTAMP PRIMARY KEY,
        hour INT NOT NULL,
        day INT NOT NULL,
        week INT NOT NULL,
        month INT NOT NULL,
        year INT NOT NULL,
        weekday INT NOT NULL
    );
""")

songplay_table_create = ("""
    CREATE TABLE IF NOT EXISTS songplays (
        songplay_id SERIAL PRIMARY KEY,
        start_time TIMESTAMP NOT NULL,
        user_id INT NOT NULL,
        level VARCHAR NOT NULL,
        song_id VARCHAR,
        artist_id VARCHAR,
        session_id INT NOT NULL,
        location VARCHAR,
        user_agent VARCHAR,
        FOREIGN KEY (user_id) REFERENCES users(user_id) ON DELETE CASCADE,
        FOREIGN KEY (song_id) REFERENCES songs(song_id) ON DELETE CASCADE,
        FOREIGN KEY (artist_id) REFERENCES artists(artist_id) ON DELETE CASCADE
    );
""")

# INSERT RECORDS

user_table_insert = ("""
    INSERT INTO users (user_id, first_name, last_name, gender, level)
        VALUES (%s, %s, %s, %s, %s)
        ON CONFLICT (user_id)
        DO UPDATE SET level=EXCLUDED.level
""")

song_table_insert = ("""
    INSERT INTO songs (song_id, title, artist_id, year, duration)
        VALUES (%s, %s, %s, %s, %s)
        ON CONFLICT (song_id)
        DO NOTHING
""")

artist_table_insert = ("""
    INSERT INTO artists (artist_id, name, location, latitude, longitude)
        VALUES (%s, %s, %s, %s, %s)
        ON CONFLICT (artist_id)
        DO NOTHING
""")

time_table_insert = ("""
    INSERT INTO time (start_time, hour, day, week, month, year, weekday)
        VALUES (%s, %s, %s, %s, %s, %s, %s)
        ON CONFLICT (start_time)
        DO NOTHING
""")

songplay_table_insert = ("""
    INSERT INTO songplays (start_time, user_id, level, song_id, artist_id, session_id, location, user_agent)
        VALUES (%s, %s, %s, %s, %s, %s, %s, %s)
""")

# FIND SONGS

song_select = ("""
    SELECT s.song_id, a.artist_id FROM songs s
        JOIN artists a ON s.artist_id = a.artist_id
        WHERE s.title = %s
        AND a.name = %s
        AND s.duration = %s;
""")

# QUERY LISTS

create_table_queries = [user_table_create, song_table_create, artist_table_create,
                        time_table_create, songplay_table_create]
drop_table_queries = [songplay_table_drop, user_table_drop, song_table_drop, artist_table_drop, time_table_drop]