4.2-结构化搜索
2020-03-30 本文已影响0人
落日彼岸
结构化数据
-
结构化搜索（Structured search） 是指对结构化数据的搜索
- ⽇期，布尔类型和数字都是结构化的
-
⽂本也可以是结构化的。
-
如彩⾊笔可以有离散的颜⾊集合：红（red）、绿（green）、蓝（blue）
-
⼀个博客可能被标记了标签，例如，分布式（distributed） 和 搜索（search）
-
电商⽹站上的商品都有 UPCs（通⽤产品码 Universal Product Codes）或其他的唯⼀标识，它们都需要遵从严格规定的、结构化的格式。
-
ES 中的结构化搜索
-
布尔，时间，⽇期和数字这类结构化数据：有精确的格式，我们可以对这些格式进⾏逻辑操作。包括⽐较数字或时间的范围，或判定两个值的⼤⼩。
-
结构化的⽂本可以做精确匹配或者部分匹配
- Term 查询 / Prefix 前缀查询
-
结构化结果只有"是"或"否"两个值
- 根据场景需要，可以决定结构化搜索是否需要打分
布尔值
#对布尔值 match 查询，有算分
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"term": {
"avaliable": true
}
}
}
#对布尔值，通过constant score 转成 filtering，没有算分
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"constant_score": {
"filter": {
"term": {
"avaliable": true
}
}
}
}
}
数字 Range
-
gt ⼤于
-
lt ⼩于
-
gte ⼤于等于
-
lte ⼩于等于
#数字类型 Term
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"term": {
"price": 30
}
}
}
#数字类型 terms
POST products/_search
{
"query": {
"constant_score": {
"filter": {
"terms": {
"price": [
"20",
"30"
]
}
}
}
}
}
#数字 Range 查询
GET products/_search
{
"query" : {
"constant_score" : {
"filter" : {
"range" : {
"price" : {
"gte" : 20,
"lte" : 30
}
}
}
}
}
}
日期 range
-
Date Math Expressions
- 2014-01-01 00:00:00||+1M
| 字段 | 含义 |
|---|---|
| y | 年 |
| M | 月 |
| w | 周 |
| d | 天 |
| H/h | 小时 |
| m | 分钟 |
| s | 秒 |
# 日期 range
POST products/_search
{
"query" : {
"constant_score" : {
"filter" : {
"range" : {
"date" : {
"gte" : "now-1y"
}
}
}
}
}
}
处理空值
#exists查询
POST products/_search
{
"query": {
"constant_score": {
"filter": {
"exists": {
"field": "date"
}
}
}
}
}
POST products/_search
{
"query": {
"constant_score": {
"filter": {
"bool": {
"must_not" : {
"exists" : {
"field" : "date"
}
}
}
}
}
}
}
查找多个精确值
POST products/_search
{
"query": {
"constant_score": {
"filter": {
"terms": {
"price": [
"20",
"30"
]
}
}
}
}
}
POST products/_search
{
"query": {
"constant_score": {
"filter": {
"terms": {
"productID.keyword": [
"JODL-X-1937-#pV7",
"QQPX-R-3956-#aD8"
]
}
}
}
}
}
包含⽽不是相等
#处理多值字段，term 查询是包含，而不是等于
POST movies/_search
{
"query": {
"constant_score": {
"filter": {
"term": {
"genre.keyword": "Comedy"
}
}
}
}
}
//res
{
"_index" : "movies",
"_type" : "_doc",
"_id" : "4399",
"_score" : 1.0,
"_source" : {
"genre" : [
"Comedy",
"Drama"
],
"title" : "Diary of a Chambermaid",
"year" : 0,
"@version" : "1",
"id" : "4399"
}
},
{
"_index" : "movies",
"_type" : "_doc",
"_id" : "4402",
"_score" : 1.0,
"_source" : {
"genre" : [
"Comedy"
],
"title" : "Dr. Goldfoot and the Bikini Machine",
"year" : 1965,
"@version" : "1",
"id" : "4402"
}
},
-
解决⽅案：增加个 genrecont 字段进⾏计数;
-
会在组合 Query & Filtering 给出解决方法;
-
会在组合 bool query 给出解决方法
本节知识点回顾
-
结构化数据 & 结构化搜索
- 如果不需要算分，可以通过 Constant Score，将查询转为 Filtering
-
范围查询和 Date Math
-
使⽤ Exist 查询处理⾮空 Null 值
-
精确值 & 多值字段的精确值查找
- Term 查询是包含，不是完全相等。针对多值字段查询要尤其注意
课程demo
#结构化搜索，精确匹配
DELETE products
POST /products/_bulk
{ "index": { "_id": 1 }}
{ "price" : 10,"avaliable":true,"date":"2018-01-01", "productID" : "XHDK-A-1293-#fJ3" }
{ "index": { "_id": 2 }}
{ "price" : 20,"avaliable":true,"date":"2019-01-01", "productID" : "KDKE-B-9947-#kL5" }
{ "index": { "_id": 3 }}
{ "price" : 30,"avaliable":true, "productID" : "JODL-X-1937-#pV7" }
{ "index": { "_id": 4 }}
{ "price" : 30,"avaliable":false, "productID" : "QQPX-R-3956-#aD8" }
GET products/_mapping
#对布尔值 match 查询，有算分
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"term": {
"avaliable": true
}
}
}
#对布尔值，通过constant score 转成 filtering，没有算分
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"constant_score": {
"filter": {
"term": {
"avaliable": true
}
}
}
}
}
#数字类型 Term
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"term": {
"price": 30
}
}
}
#数字类型 terms
POST products/_search
{
"query": {
"constant_score": {
"filter": {
"terms": {
"price": [
"20",
"30"
]
}
}
}
}
}
#数字 Range 查询
GET products/_search
{
"query" : {
"constant_score" : {
"filter" : {
"range" : {
"price" : {
"gte" : 20,
"lte" : 30
}
}
}
}
}
}
# 日期 range
POST products/_search
{
"query" : {
"constant_score" : {
"filter" : {
"range" : {
"date" : {
"gte" : "now-1y"
}
}
}
}
}
}
#exists查询
POST products/_search
{
"query": {
"constant_score": {
"filter": {
"exists": {
"field": "date"
}
}
}
}
}
#处理多值字段
POST /movies/_bulk
{ "index": { "_id": 1 }}
{ "title" : "Father of the Bridge Part II","year":1995, "genre":"Comedy"}
{ "index": { "_id": 2 }}
{ "title" : "Dave","year":1993,"genre":["Comedy","Romance"] }
#处理多值字段，term 查询是包含，而不是等于
POST movies/_search
{
"query": {
"constant_score": {
"filter": {
"term": {
"genre.keyword": "Comedy"
}
}
}
}
}
#字符类型 terms
POST products/_search
{
"query": {
"constant_score": {
"filter": {
"terms": {
"productID.keyword": [
"QQPX-R-3956-#aD8",
"JODL-X-1937-#pV7"
]
}
}
}
}
}
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"match": {
"price": 30
}
}
}
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"term": {
"date": "2019-01-01"
}
}
}
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"match": {
"date": "2019-01-01"
}
}
}
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"constant_score": {
"filter": {
"term": {
"productID.keyword": "XHDK-A-1293-#fJ3"
}
}
}
}
}
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"term": {
"productID.keyword": "XHDK-A-1293-#fJ3"
}
}
}
#对布尔数值
POST products/_search
{
"query": {
"constant_score": {
"filter": {
"term": {
"avaliable": "false"
}
}
}
}
}
POST products/_search
{
"query": {
"term": {
"avaliable": {
"value": "false"
}
}
}
}
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"term": {
"price": {
"value": "20"
}
}
}
}
POST products/_search
{
"profile": "true",
"explain": true,
"query": {
"match": {
"price": "20"
}
}
}
}
POST products/_search
{
"query": {
"constant_score": {
"filter": {
"bool": {
"must_not": {
"exists": {
"field": "date"
}
}
}
}
}
}
}
相关阅读
https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-exists-query.html
https://www.elastic.co/guide/en/elasticsearch/reference/7.1/term-level-queries.html
