Solr的学习使用之(七)Solr高级查询facet、facet.pivot简介 - OnTheRoad_Lee

1 、什么是Faceted Search

Facet['fæsɪt]很难翻译,只能靠例子来理解了。Solr作者Yonik Seeley也给出更为直接的名字:导航(Guided Navigation)、参数化查询(Paramatic Search)。

image

上面是比较直接的Faceted Search例子,品牌、产品特征、卖家,均是 Facet 。而Apple、Lenovo等品牌,就是 Facet values 或者说 Constraints ,而Facet values所带的统计值就是 Facet count/Constraint count 。

2 、Facet 使用

q = 超级本 
facet = true 
facet.field = 产品特性 
facet.field = 品牌 
facet.field = 卖家

http://…/select?q=超级本&facet=true&wt=json

&facet.field=品牌&facet.field=产品特性&facet.field=卖家

也可以提交查询条件,设置fq(filter query)。

q = 电脑 
facet = true 
fq = 价格:[8000 TO *] 
facet.mincount = 1 // fq将不符合的字段过滤后,会显示count为0 
facet.field = 产品特性 
facet.field = 品牌 
facet.field = 卖家

http://…/select?q=超级本&facet=true&wt=json

&fq=价格:[8000 TO *]&facet.mincount=1

&facet.field=品牌&facet.field=产品特性&facet.field=卖家

"facet_counts": {
"facet_fields": {
  "品牌": [
    "Apple", 4,
    "Lenovo", 39
      …]
  "产品特性": [
    "显卡", 42,
    "酷睿", 38
      …]
 
  …}}

如果用户选择了Apple这个分类,查询条件中需要添加另外一个fq查询条件,并移除Apple所在的facet.field。

http://…/select?q=超级本&facet=true&wt=json

&fq=价格:[8000 TO *]&fq=品牌:Apple&facet.mincount=1

&facet.field= 品牌 &facet.field=产品特性&facet.field=卖家

3 、Facet 参数

facet.prefix  –   限制constaints的前缀

facet.mincount=0 –  限制constants count的最小返回值,默认为0

facet.sort=count –  排序的方式,根据count或者index

facet.offset=0  –   表示在当前排序情况下的偏移,可以做分页

facet.limit=100 –  constraints返回的数目

facet.missing=false –  是否返回没有值的field

facet.date –  Deprecated, use facet.range

facet.query

指定一个查询字符串作为Facet Constraint

facet.query = rank:[* TO 20]

facet.query = rank:[21 TO *]

"facet_counts": {
"facet_fields": {
  "品牌": [
    "Apple", 4,
    "Lenovo", 10
      …]
  "产品特性": [
    "显卡", 11,
    "酷睿", 20
      …]
 
  …}}

facet.range

http://…/select?&facet=true

&facet.range=price

&facet.range.start=5000

&facet.range.end=8000

&facet.range.gap=1000

<result numFound="27" ... />
 ...
 <lst name="facet_counts">
 <lst name="facet_queries">
   <int name="rank:[* TO 20]">2</int>
   <int name="rank:[21 TO *]">15</int>
 </lst>
...

WARNING:  range范围是左闭右开,[start, end)

facet.pivot

这个是Solr 4.0的新特性,pivot和facet一样难理解,还是用例子来讲吧。

Syntax:  facet.pivot=field1,field2,field3...

e.g.  facet.pivot=comment_user, grade

#docs

#docs grade:好

#docs 等级:中

#docs 等级:差

comment_user:1

10

8

1

1

comment_user:2

20

18

2

0

comment_user:3

15

12

2

1

comment_user:4

18

15

2

1

"facet_counts":{
"facet_pivot":{
 "comment_user, grade ":[{
   "field":"comment_user",
   "value":"1",
   "count":10,
   "pivot":[{
     "field":"grade",
     "value":"",
     "count":8}, {
     "field":"grade",
     "value":"",
     "count":1}, {
     "field":"grade",
     "value":"",
     "count":1}]
   }, {
     "field":" comment_user ",
     "value":"2",
     "count":20,
     "pivot":[{
      …

没有pivot机制的话,要做到上面那点可能需要多次查询:

http://...q= comment&fq= grade:好&facet=true&facet.field=comment_user

http://...q=comment&fq=grade:中&facet=true&facet.field=comment_user

http://...q=comment&fq=grade:差&facet=true&facet.field=comment_user

Facet.pivot -  Computes a Matrix of Constraint Counts across multiple Facet Fields. by Yonik Seeley.

上面那个解释很不错,只能理解不能翻译。

posted on 2014-06-24 12:23  分布式编程  阅读(84)  评论(0编辑  收藏  举报

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