roster_trackdB.py

import json
import sqlite3

conn = sqlite3.connect('rosterdb.sqlite')
cur = conn.cursor()

# Drop existing tables
cur.executescript('''
DROP TABLE IF EXISTS User;
DROP TABLE IF EXISTS Course;
DROP TABLE IF EXISTS Member;

CREATE TABLE User (
    id     INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
    name   TEXT UNIQUE
);

CREATE TABLE Course (
    id     INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
    title  TEXT UNIQUE
);

-- NOTE: role is REQUIRED for this assignment
CREATE TABLE Member (
    user_id    INTEGER,
    course_id  INTEGER,
    role       INTEGER,
    PRIMARY KEY (user_id, course_id)
);
''')

fname = 'roster_data.json'
str_data = open(fname, 'r', encoding='utf-8').read()
json_data = json.loads(str_data)

# json_data is like:
# [
#   ["Name", "Course", 1],
#   ["Name2", "Course2", 0],
#   ...
# ]

for entry in json_data:
    name = entry[0]
    title = entry[1]
    role = entry[2]

    # Insert user
    cur.execute('INSERT OR IGNORE INTO User (name) VALUES (?)', (name,))
    cur.execute('SELECT id FROM User WHERE name = ?', (name,))
    user_id = cur.fetchone()[0]

    # Insert course
    cur.execute('INSERT OR IGNORE INTO Course (title) VALUES (?)', (title,))
    cur.execute('SELECT id FROM Course WHERE title = ?', (title,))
    course_id = cur.fetchone()[0]

    # Insert membership with role
    cur.execute('''
        INSERT OR REPLACE INTO Member (user_id, course_id, role)
        VALUES (?, ?, ?)
    ''', (user_id, course_id, role))

conn.commit()
cur.close()
conn.close()

print("Database created: rosterdb.sqlite")