ZaXrJ80u

1from cassandra.cluster import Cluster
2from cassandra.query import dict_factory
3
4def create_keyspace(session, keyspace):
5    session.execute("""
6            CREATE KEYSPACE IF NOT EXISTS """+keyspace+"""
7            WITH replication = { 'class': 'SimpleStrategy', 'replication_factor': '1' }
8                    """)
9
10def create_table(session, keyspace, table):
11    session.execute("""
12            CREATE TABLE IF NOT EXISTS """+ keyspace+"""."""+table+""" (
13            user_id int ,
14            avg_movie_rating float,
15            PRIMARY KEY(user_id)
16            )
17            """)
18
19def push_data_table(session, keyspace, table, userId, avgMovieRating):
20    session.execute(
21        """
22        INSERT INTO """+keyspace+"""."""+table+""" (user_id, avg_movie_rating)
23        VALUES (%(user_id)s, %(avg_movie_rating)s)
24        """,
25        {
26            'user_id': userId,
27            'avg_movie_rating': avgMovieRating
28        }
29        )
30
31def get_data_table(session, keyspace, table):
32    rows = session.execute("SELECT * FROM "+keyspace+"."+table+";")
33    print("he"*8)
34    print(type(rows))
35    for row in rows:
36        print(row)
37
38def clear_table(session, keyspace, table):
39    session.execute("TRUNCATE "+keyspace+"."+table+";")
40
41def delete_table(session, keyspace, table):
42    session.execute("DROP TABLE "+keyspace+"."+table+";")
43
44if __name__ == "__main__":
45    keyspace = "user_ratings"
46    table = "user_avg_rating"
47    # utworzenia połączenia z klastrem
48    cluster = Cluster(['127.0.0.1'], port=9042)
49    session = cluster.connect()
50    # utworzenie nowego keyspace
51    create_keyspace(session, keyspace)
52    # ustawienie używanego keyspace w sesji
53    session.set_keyspace(keyspace)
54    # użycie dict_factory pozwala na zwracanie słowników
55    # znanych z języka Python przy zapytaniach do bazy danych
56    session.row_factory = dict_factory
57    # tworzenie tabeli
58    create_table(session, keyspace, table)
59    # umieszczanie danych w tabeli
60    push_data_table(session, keyspace, table, userId=1337, avgMovieRating=4.2)
61    # pobieranie zawartości tabeli i wyświetlanie danych
62    get_data_table(session, keyspace, table)
63    # czyszczenie zawartości tabeli
64    clear_table(session, keyspace, table)
65    get_data_table(session, keyspace, table)
66    # usuwanie tabeli
67    delete_table(session, keyspace, table)