MongoDB在創(chuàng)建集合的時候就在_id字段創(chuàng)建了一個唯一性索引. 這個索引防止客戶端插入兩個擁有相同_id的文檔娇唯，并且這個索引不可被刪除齐遵。
MongoDB索引使用的是B-tree數(shù)據(jù)結構。
創(chuàng)建索引
db.collection.createIndex()
單個字段創(chuàng)建索引
db.books.createIndex({name:1},{ unique: true })#在name上創(chuàng)建唯一性索引
復合索引
MongoDB規(guī)定限制復合的字段最多只能是31個塔插。
db.userlist.createIndex({name:1,score:1})
多鍵索引
1.數(shù)組元素
db.userlist.createIndex({"habbit":1});
2.含有文檔的數(shù)組元素
db.userlist.createIndex({"books.name":1,"books.pages":1})
文本索引
1.創(chuàng)建文本索引
db.news.createIndex({title:'text',content:'text'})
db.collection.createIndex( { "$**": "text" } )#創(chuàng)建多個
指定索引名稱：
db.news.createIndex({title:'text',content:'text'},{name:'tilte_content_index'})
根據(jù)索引名稱刪除索引:
db.collection.dropIndex("tilte_content_index")
3.數(shù)據(jù)準備
db.news.insertMany([
{title:'aa bb cc ',content:'cc rice'},
{title:'bb cc ',content:'dd ee'},
{title:'ee bb aa ',content:'cc'},
{title:'aa dd',content:'ee'},
{title:'aa bb',content:'ae'},
{title:'rice cc dd ',content:'aa'}
])
4.檢索：
- 單個關鍵字
db.news.find({$text:{$search:"aa"}})
查找結果：
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa1"), "title" : "aa bb cc ", "content" : "cc rice" }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa6"), "title" : "rice cc dd ", "content" : "aa" }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa5"), "title" : "aa bb", "content" : "ae" }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa4"), "title" : "aa dd", "content" : "ee" }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa3"), "title" : "ee bb aa ", "content" : "cc" }
- 多個關鍵字(或關系):空格隔開
db.news.find({$text:{$search:"aa cc"}})
顯示結果：
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa2"), "title" : "bb cc ", "content" : "dd ee" }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa1"), "title" : "aa bb cc ", "content" : "cc rice" }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa6"), "title" : "rice cc dd ", "content" : "aa" }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa5"), "title" : "aa bb", "content" : "ae" }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa4"), "title" : "aa dd", "content" : "ee" }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa3"), "title" : "ee bb aa ", "content" : "cc" }
- 多個關鍵字（與關系）: \"包住關鍵字
db.news.find({$text:{$search:"\"aa\" \"cc\""}})
查詢結果：
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa1"), "title" : "aa bb cc ", "content" : "cc rice" }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa6"), "title" : "rice cc dd ", "content" : "aa" }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa3"), "title" : "ee bb aa ", "content" : "cc" }
- 查詢多個關鍵梗摇，排除某個關鍵字
db.news.find({$text:{$search:"\"aa\" \"cc\" -rice"}})
顯示結果：
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa3"), "title" : "ee bb aa ", "content" : "cc" }
相似度查詢：
db.news.find(
{"$text":{"$search":"aa cc"}},
{"score":{"$meta":"textScore"}}
).sort({"score":
{"$meta":"textScore"}
});
查詢結果：
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa1"), "title" : "aa bb cc ", "content" : "cc rice", "score" : 2.083333333333333 }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa3"), "title" : "ee bb aa ", "content" : "cc", "score" : 1.7666666666666666 }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa6"), "title" : "rice cc dd ", "content" : "aa", "score" : 1.7666666666666666 }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa2"), "title" : "bb cc ", "content" : "dd ee", "score" : 0.75 }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa4"), "title" : "aa dd", "content" : "ee", "score" : 0.75 }
{ "_id" : ObjectId("599f03272aa12cb8dc4dcaa5"), "title" : "aa bb", "content" : "ae", "score" : 0.75 }
2d球面索引
2d索引
1.創(chuàng)建索引
db.shop.createIndex({"loc":"2d"})
2.插入數(shù)據(jù)
db.shop.insertMany([{name:'蘭州拉面',loc:[11,12]},
{name:'番茄妹米線',loc:[11,11]},
{name:'香格里拉',loc:[10,12]},
{name:'座上客',loc:[11,52]},
{name:'蘇果超市',loc:[41,42]},
{name:'一鳴奶品',loc:[31,32]},
{name:'和善園',loc:[21,22]}]);
3.檢索：
db.shop.find({loc:{$near:[11,11],$maxDistance:5}});
4.檢索結果：
{ "_id" : ObjectId("599f192d2aa12cb8dc4dcaaf"), "name" : "番茄妹米線", "loc" : [ 11, 11 ] }
{ "_id" : ObjectId("599f192d2aa12cb8dc4dcaae"), "name" : "蘭州拉面", "loc" : [ 11, 12 ] }
{ "_id" : ObjectId("599f192d2aa12cb8dc4dcab0"), "name" : "香格里拉", "loc" : [ 10, 12 ] }
