如何从neo4j返回所有最新节点? [英] How to return all newest nodes from neo4j?
问题描述
是否可以向neo4j查询最新节点?在这种情况下,索引属性"timestamp"以毫秒为单位记录每个节点上的时间.
Is it possible to query neo4j for the newest nodes? In this case, the indexed property "timestamp" records time in milliseconds on every node.
我发现的所有密码示例都涉及图类型查询-从节点n开始并遵循关系.返回在一个字段上排序的结果集的最佳方法是什么?在图数据库(如node4j?
All of the cypher examples I have lfound concern graph-type queries- "start at node n and follow relationships. What is the general best approach for returning resultsets sorted on one field? Is this even possible in a graph database such as node4j?
推荐答案
在嵌入式Java API中,可以使用Lucene构造添加排序.
In the embedded Java API it is possible to add sorting using Lucene constructs.
http://docs.neo4j.org/chunked /milestone/indexing-lucene-extras.html#indexing-lucene-query-objects http://blog.richeton.com/2009/05/12/lucene-sort-tips /
在服务器模式下,您可以将?order
参数传递给lucene查找查询.
In the server mode you can pass an ?order
parameter to the lucene lookup query.
http://docs.neo4j .org/chunked/milestone/rest-api-indexes.html#rest-api-find-node-by-query
取决于您对数据建立索引的方式(不是数字方式,因为lucene查询语法解析器和数字搜索:()存在问题,在cypher中,您可以这样做:
Depending on how you indexed your data (not numerically as there are issues with the lucene query syntax parser and numeric searches :( ), in cypher you can do:
start n=node:myindes('time: [1 to 1000]') return n order by n.time asc
还有更多图形方法可以做到这一点,例如通过以NEXT
关系链接事件并返回此列表的head和next n个元素
There are also more graphy ways of doing that, e.g. by linking the events with a NEXT
relationship and returning the head and next n elements from this list
http://docs.neo4j.org/chunked/milestone/cypher-cookbook-newsfeed .html
或创建时间树结构:
http://docs.neo4j.org/chunked/milestone/cypher-cookbook -path-tree.html
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