Question

我打算将数据插入到带有复合键的CF下面。

CREATE TABLE event_attend (
    event_id int,
    event_type varchar,
    event_user_id int,
    PRIMARY KEY (event_id, event_type)    #compound keys...
);

但我无法使用cql从python向此CF插入数据。（http://code.google.com/a/apache-extras.org/p/cassandra-dbapi2/）

import cql
connection = cql.connect(host, port, keyspace)
cursor = connection.cursor()
cursor.execute("INSERT INTO event_attend (event_id, event_type, event_user_id) VALUES (1, 'test', 2)", dict({}) )

我得到以下追溯：

Traceback (most recent call last):
File "./v2_initial.py", line 153, in <module>
  db2cass.execute()
File "./v2_initial.py", line 134, in execute
  cscursor.execute("insert into event_attend (event_id, event_type, event_user_id ) values (1, 'test', 2)", dict({}))
File "/usr/local/pythonbrew/pythons/Python-2.7.2/lib/python2.7/site-packages/cql-1.4.0-py2.7.egg/cql/cursor.py", line 80, in execute
  response = self.get_response(prepared_q, cl)
File "/usr/local/pythonbrew/pythons/Python-2.7.2/lib/python2.7/site-packages/cql-1.4.0-py2.7.egg/cql/thrifteries.py", line 80, in get_response
  return self.handle_cql_execution_errors(doquery, compressed_q, compress)
File "/usr/local/pythonbrew/pythons/Python-2.7.2/lib/python2.7/site-packages/cql-1.4.0-py2.7.egg/cql/thrifteries.py", line 98, in handle_cql_execution_errors
  raise cql.ProgrammingError("Bad Request: %s" % ire.why)
cql.apivalues.ProgrammingError: Bad Request: unable to make int from 'event_user_id'

我做错了什么？

Answer 1

看起来您正在尝试按照以下示例进行操作： http://pypi.python.org/pypi/cql/1.4.0

import cql
con = cql.connect(host, port, keyspace)
cursor = con.cursor()
cursor.execute("CQL QUERY", dict(kw='Foo', kw2='Bar', kwn='etc...'))

但是，如果你只需要插入一行（就像你的问题一样），只需删除空的dict（）参数。

此外，由于您使用的是复合键，因此请确保使用CQL3 http://www.datastax.com/dev/blog/whats-new-in-cql-3-0

connection = cql.connect('localhost:9160', cql_version='3.0.0')

以下代码应该有效（如果需要，只需将其调整为localhost）：

import cql
con = cql.connect('172.24.24.24', 9160,  keyspace, cql_version='3.0.0')
print ("Connected!")
cursor = con.cursor()
CQLString = "INSERT INTO event_attend (event_id, event_type, event_user_id) VALUES (131, 'Party', 3156);"
cursor.execute(CQLString)

Answer 2

对于python 2.7、3.3、3.4、3.5和3.6进行安装，您可以使用

     $ pip install cassandra-driver

在python中：

     import cassandra

文档可以在https://datastax.github.io/python-driver/getting_started.html#passing-parameters-to-cql-queries下找到

使用cql从python插入cassandra

2 个答案: