NFemLhCw

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