I try to access my local cassandra database via python. Therefore I
installed db-api 2.0 and thrift for accessing the database. Opening
and closing a connection works fine. But a simply query is not
working:
The script looks like this:
c = conn.cursor()
c.execute("""select * from users;""")
data = c.fetchall()
print "Query: select * from users; returned the following result:"
print str(data)
The table users looks like this:
qlsh:demodb> select * from users;
user_name | birth_year | gender | password | session_token | state
-----------+------------+--------+----------+---------------+-------
jsmith | null | null | secret | null | null
But when I try to execute it I get the following error:
Open connection to localhost:9160 on keyspace demodb
Traceback (most recent call last):
File
"/Users/Tom/Freelancing/Company/Python/ApacheCassandra/src/CassandraDemo.py",
line 56, in <module>
perfromSimpleCQLQuery()
File
"/Users/Tom/Freelancing/Company/Python/ApacheCassandra/src/CassandraDemo.py",
line 46, in perfromSimpleCQLQuery
c.execute("""select * from users;""")
File "/Library/Python/2.7/site-packages/cql/cursor.py", line 81, in execute
return self.process_execution_results(response, decoder=decoder)
File "/Library/Python/2.7/site-packages/cql/thrifteries.py", line
116, in process_execution_results
self.get_metadata_info(self.result[0])
File "/Library/Python/2.7/site-packages/cql/cursor.py", line 97, in
get_metadata_info
name, nbytes, vtype, ctype = self.get_column_metadata(colid)
File "/Library/Python/2.7/site-packages/cql/cursor.py", line 104, in
get_column_metadata
return self.decoder.decode_metadata_and_type(column_id)
File "/Library/Python/2.7/site-packages/cql/decoders.py", line 45,
in decode_metadata_and_type
name = self.name_decode_error(e, namebytes,
comptype.cql_parameterized_type())
File "/Library/Python/2.7/site-packages/cql/decoders.py", line 29,
in name_decode_error
% (namebytes, expectedtype, err))
cql.apivalues.ProgrammingError: column name '\x00\x00\x00' can't be
deserialized as 'org.apache.cassandra.db.marshal.CompositeType':
global name 'self' is not defined
I'm not shure if this is the right place to ask for: But am I doing
here something wrong?
