Cassandra和查询层次结构 [英] Cassandra and querying hierarchies

问题描述

我正在调查Cassandra，但在下列任何文件中找不到答案。

我需要在深层次结构中查询范围。我已经确定表示层次结构的最简单的方法是将每个级别作为列。例如：

 原产地价格ID 
 Europe.Germany VW Group.Audi 20000 1 
欧洲。德国VW集团.Porshe 21000 2 
欧洲。德国宝马19000 3 
  

SQL示例：

  SELECT ID FROM CompositeTable WHERE（原点STARTS WITH'Europe'）
 AND（制造商STARTS WITH' VW集团，而不是'VW集团.Porshe'或是'宝马'）
和（价格BETWEEN 18000和22000）
  

结果：

  ID = [1,3] 
  
 
 
 
 Cassandra可以在复合索引中执行此类搜索吗？
解决方案
 Cassandra中的复合键是DBMS中的一种多列索引，如果您在表中有c1，c2和c3索引列从c1到c6。 DB将总是尝试使用您的索引，如果查询是 =，> （c1），（c1，c2）或（c1，c2，c3）而不是（c2），（c2，c3），...的操作， （c3）或（c1，c3）。 case在cassandra是一样的，但在这里你有多列索引在c1到c6 [因为列首先排序基于c1和冲突转移到c2和后续] 
 
I am investigating Cassandra, but cannot find an answer in any documentation to the following.

I need to query ranges across a deep hierarchy. I have determined that the easiest way to represent the hierarchy is to have each level as a column. For example:
Origin           Manufacturer    Price    ID
Europe.Germany   VW Group.Audi   20000    1
Europe.Germany   VW Group.Porshe 21000    2
Europe.Germany   BMW             19000    3
Here is a pseudo SQL example:
SELECT ID FROM CompositeTable WHERE (Origin STARTS WITH 'Europe')
AND (Manufacturer STARTS WITH 'VW Group' AND IS NOT 'VW Group.Porshe' OR IS 'BMW')
AND (Price BETWEEN 18000 AND 22000)
Result:
ID = [1, 3]
Can Cassandra perform this type of search across a composite index?
解决方案
Composite Keys in Cassandra is a kind of multiple-column index in DBMS, where if you have index on c1, c2 and c3 in a table with columns from c1 to c6. DB will always try to use you index if the query is for =, > , <, >=, <= operation on (c1), (c1,c2) or (c1, c2, c3) but not for (c2), (c2, c3), (c3) or (c1, c3). The case is the same in cassandra but here you have multiple-column index on c1 to c6 [since the columns are sorted first based on c1 and the collision carries over to c2 and follows on]

                        
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