FluentCassandra范围内选择问题 [英] FluentCassandra range selection problem

问题描述

我有一个问题，在使用C＃和FluentCassandra得到一些数据从卡桑德拉。 在我的卡珊德拉密钥空间，我有以下的超级列族的定义：

I have a problem in getting some data out from Cassandra using c# and FluentCassandra. In my Cassandra keyspace i have the following super column family definition:

<ColumnFamily Name="MySCFName"
                    ColumnType="Super"
                    CompareWith="TimeUUIDType"

                CompareSubcolumnsWith="AsciiType"/>

我想要做的是运行supercolumnfamily类似于下面的SQL中对这样的查询：

What i would like to do is run a query on this supercolumnfamily similar to the following in sql:

select "something" from MyTable where "timestamp" between "2011-01-01 00:00:00.000" and "2011-03-01 00:00:00.000"

以下任一教程中，我发现我可以得到一些数据出来卡桑德拉用下面的命令：

Following one tutorial i found i can get some data out of Cassandra with the following command:

family.Get("238028210009775").Fetch(DateTime.Parse("2011-01-01 00:00:00.000")).FirstOrDefault();

不过这是SQL 时间戳＆GT同等学历; 2011-01-01 00：00：00.000

现在为止，我无法弄清楚如何从一个值范围检索数据。

and so far i cannot figure out how to retrieve data from a range of values.

任何提示或帮助将AP preciated :) 提前致谢， 尼古拉

Any hints or help will be appreciated :) Thanks in advance, Nicola

推荐答案

您应该可以用下面的做到这一点：

You should be able to do it with the following:

using (var db = new CassandraContext(keyspace: "keyspace_name", host: "localhost"))
{
    var fromDate = DateTime.Now.Subtract(new TimeSpan(0, 30, 0));
    var toDate = DateTime.Now;
    var family = db.GetColumnFamily<TimeUUIDType, AsciiType>("family_name");
    var results = family.Get("row_key")
                        .Fetch(fromDate)
                        .TakeUntil(toDate)
                        .FirstOrDefault();
}

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