MongoDB的簡單使用-查詢操作

標籤：ack   最大   pre   object   rac   media   find   author   ini   

MongoDB通過find()函數執行查詢操作

1.尋找集合內的全部文檔：

db.media.find()

系統返回：

{ "_id" : ObjectId("5aa47c1953350e04ddbd6fa3"), "Type" : "Book", "Title" : "Definitive Guide to MongoDB 3rd ed.", "ISBN" : "978-1-4842-1183-0", "Publisher" : "Apress", "Author" : [ "Hows,David", "Plugge,Eelco", "Membrey,Peter", "Hawkins,Tim" ] }
{ "_id" : ObjectId("5aa47dd553350e04ddbd6fa4"), "Type" : "CD", "Artist" : "Nirvana", "Title" : "Nevermind", "Tracklist" : [ { "Track" : "1", "Titie" : "Smells Like Teen Spirit", "Length" : "5:02" }, { "Track" : "2", "Title" : "In Bloom", "Length" : "4:15" } ] }

顯示出上篇文章我們添加的2個文檔

2.尋找Nirvana的所有CD：

db.media.find({Artist:"Nirvana"})

系統返回：

{ "_id" : ObjectId("5aa47dd553350e04ddbd6fa4"), "Type" : "CD", "Artist" : "Nirvana", "Title" : "Nevermind", "Tracklist" : [ { "Track" : "1", "Titie" : "Smells Like Teen Spirit", "Length" : "5:02" }, { "Track" : "2", "Title" : "In Bloom", "Length" : "4:15" } ] }

3.尋找Nirvana的所有CD的標題：

db.media.find({Artist:"Nirvana"},{Title:1})

系統返回：

{ "_id" : ObjectId("5aa47dd553350e04ddbd6fa4"), "Title" : "Nevermind" }

尋找Nirvana的所有CD的非標題資訊

db.media.find({Artist:"Nirvana"},{Title:0})

系統返回：

{ "_id" : ObjectId("5aa47dd553350e04ddbd6fa4"), "Type" : "CD", "Artist" : "Nirvana", "Tracklist" : [ { "Track" : "1", "Titie" : "Smells Like Teen Spirit", "Length" : "5:02" }, { "Track" : "2", "Title" : "In Bloom", "Length" : "4:15" } ] }

4.尋找內嵌對象文檔的資訊：

db.media.find({"Tracklist.Title":"In Bloom"})

系統將返回對應文檔的全部資訊

{ "_id" : ObjectId("5aa47dd553350e04ddbd6fa4"), "Type" : "CD", "Artist" : "Nirvana", "Title" : "Nevermind", "Tracklist" : [ { "Track" : "1", "Titie" : "Smells Like Teen Spirit", "Length" : "5:02" }, { "Track" : "2", "Title" : "In Bloom", "Length" : "4:15" } ] }

5其他相關函數

　　sort()排序函數 db.media.find().sort({Title:1})      #1為升序，-1為降序

　　limit()限制返回結果的最大數目 db.media.find().limit(10)      #0表示返回所有結果

　　skip()忽略集合中的前幾個文檔 db.media.find().skip(20)      

MongoDB的簡單使用-查詢操作