我有代码
from uuid import uuid4
from uuid import uuid1
from cassandra.cqlengine import columns, connection
from cassandra.cqlengine.models import Model
from cassandra.cqlengine.management import sync_table
class BaseModel(Model):
__abstract__ = True
id = columns.UUID(primary_key=True, default=uuid4)
created_timestamp = columns.TimeUUID(primary_key=True,
clustering_order='DESC',
default=uuid1)
deleted = columns.Boolean(required=True, default=False)
class OtherModel(BaseModel):
__table_name__ = 'other_table'
name = columns.Text(required=True, default='')
if __name__ == '__main__':
connection.setup(hosts=['localhost'],
default_keyspace='test')
sync_table(OtherModel)
now()
中有cassandra
个功能,可让current time
创建记录。
我尝试使用INSERT
查询创建记录。
cqlsh> INSERT INTO test.other_table ("id", "created_timestamp", "deleted", "name") VALUES (3c156369-6d71-40e2-933f-b48fdda7681f, now(), false, 'test');
但是当我尝试
时created_timestamp = columns.TimeUUID(primary_key=True,
clustering_order='DESC',
default='now()')
验证时出错。
我尝试覆盖TimeUUID
列,并从now()
函数返回validate
。
但它插入了插入记录。
2017-01-16 12:20:06 [DEBUG] cassandra.cqlengine.connection: INSERT INTO test.other_table ("deleted", "id", "created_timestamp", "name") VALUES (%(0)s, %(1)s, %(2)s, %(3)s)
...
...
result = session.execute(query, params, timeout=timeout)
File "cassandra/cluster.py", line 1710, in cassandra.cluster.Session.execute (cassandra/cluster.c:30976)
return self.execute_async(query, parameters, trace, custom_payload, timeout).result()
File "cassandra/cluster.py", line 3343, in cassandra.cluster.ResponseFuture.result (cassandra/cluster.c:68510)
raise self._final_exception
InvalidRequest: Error from server: code=2200 [Invalid query] message="Invalid STRING constant (now()) for "created_timestamp" of type timeuuid"
我尝试使用直接插入查询。
from cassandra.cqlengine import connection
if __name__ == '__main__':
connection.setup(hosts=['localhost'],
default_keyspace='test')
session = connection.get_session()
insert_query = """INSERT INTO test.other_table ("id", "created_timestamp", "deleted", "name") VALUES (%(0)s, %(1)s, %(2)s, %(3)s)"""
params = {'0': '3c156369-6d71-40e2-933f-b48fdda7681f', '2': False, '3': 'name', '1': 'now()'}
session.execute(insert_query, params)
但这也给出了同样的错误:(。
有没有办法从default
驱动程序中传递python
中的cassandra函数?
答案 0 :(得分:1)
它不喜欢将now()
作为参数传递。通过从now()
中删除params
并将其添加到VALUES子句中的查询字符串,我能够让您的(较低)代码正常工作:
insert_query = """INSERT INTO other_table
("id", "created_timestamp", "deleted", "name")
VALUES (%(0)s, now(), %(1)s, %(2)s)"""
session.execute(insert_query, params)
...
aploetz@cqlsh:stackoverflow> SELECT * FROm other_table ;
id | created_timestamp | deleted | name
--------------------------------------+--------------------------------------+---------+------
3c156369-6d71-40e2-933f-b48fdda7681f | da509470-dcc9-11e6-b047-2ff6499dee60 | False | name
(1 rows)