MongoDB簡介
MongoDB 是一個基于分布式文件存儲的數據庫。由 C++ 語言編寫。旨在為 WEB 應用提供可擴展的高性能數據存儲解決方案。
MongoDB 是一個介于關系數據庫和非關系數據庫之間的產品，是非關系數據庫當中功能最豐富，最像關系數據庫的。
下面給大家介紹MongoDB查詢文檔操作的實例
先把student刪除，再重新插入數據
> db.student.drop()true> db.student.insert([{ "_id" : 1, "name" : "zhangsan", "age": 27, "sex": 1 }, { "_id" : 2, "name" : "lisi", "age": 27 } ,{ "_id" : 3, "name" : "wangwu", "age": 30 }, { "_id" : 4, "name" : "zhaoliu", "age": 28 }, { "_id" : 5, "name" : "qianliu", "age": 33 }, { "_id" : 6, "name" : "sunba", "age": 32 }])BulkWriteResult({"writeErrors" : [ ],"writeConcernErrors" : [ ],"nInserted" : 6,"nUpserted" : 0,"nMatched" : 0,"nModified" : 0,"nRemoved" : 0,"upserted" : [ ]})> db.student.find(){ "_id" : 1, "name" : "zhangsan", "age" : 27 }{ "_id" : 2, "name" : "lisi", "age" : 27 }{ "_id" : 3, "name" : "wangwu", "age" : 30 }{ "_id" : 4, "name" : "zhaoliu", "age" : 28 }{ "_id" : 5, "name" : "qianliu", "age" : 33 }{ "_id" : 6, "name" : "sunba", "age" : 32 } 1、查詢指定鍵
db.集合名稱.find({查詢條件},{指定鍵})
指定鍵：1表示顯示，0表示不顯示，_id默認顯示
> db.student.find({},{name:1}){ "_id" : 1, "name" : "zhangsan" }{ "_id" : 2, "name" : "lisi" }{ "_id" : 3, "name" : "wangwu" }{ "_id" : 4, "name" : "zhaoliu" }{ "_id" : 5, "name" : "qianliu" }{ "_id" : 6, "name" : "sunba" }> db.student.find({},{_id:0, age:0}){ "name" : "zhangsan", "sex" : 1 }{ "name" : "lisi" }{ "name" : "wangwu" }{ "name" : "zhaoliu" }{ "name" : "qianliu" }{ "name" : "sunba" }> db.student.find({},{_id:0, name:1}){ "name" : "zhangsan" }{ "name" : "lisi" }{ "name" : "wangwu" }{ "name" : "zhaoliu" }{ "name" : "qianliu" }{ "name" : "sunba" } 2、各種查詢方式
$lt:<$lte:<=$gt:>$gte:>=$ne:!=> db.student.find({age:{$lt:30}}){ "_id" : 1, "name" : "zhangsan", "age" : 27, "sex" : 1 }{ "_id" : 2, "name" : "lisi", "age" : 27 }{ "_id" : 4, "name" : "zhaoliu", "age" : 28 }> db.student.find({age:{$ne:27}}){ "_id" : 3, "name" : "wangwu", "age" : 30 }{ "_id" : 4, "name" : "zhaoliu", "age" : 28 }{ "_id" : 5, "name" : "qianliu", "age" : 33 }{ "_id" : 6, "name" : "sunba", "age" : 32 } $in:包含
$nin:不包含
> db.student.find({age:{$in:[27,28]}}){ "_id" : 1, "name" : "zhangsan", "age" : 27, "sex" : 1 }{ "_id" : 2, "name" : "lisi", "age" : 27 }{ "_id" : 4, "name" : "zhaoliu", "age" : 28 }> db.student.find({age:{$nin:[27,28]}}){ "_id" : 3, "name" : "wangwu", "age" : 30 }{ "_id" : 5, "name" : "qianliu", "age" : 33 }{ "_id" : 6, "name" : "sunba", "age" : 32 } $or:或者
> db.student.find({$or:[{age:{$lt:29}}, {name:"sunba"}]}){ "_id" : 1, "name" : "zhangsan", "age" : 27, "sex" : 1 }{ "_id" : 2, "name" : "lisi", "age" : 27 }{ "_id" : 4, "name" : "zhaoliu", "age" : 28 }{ "_id" : 6, "name" : "sunba", "age" : 32 } null:空值
> db.student.find({sex: null}){ "_id" : 2, "name" : "lisi", "age" : 27 }{ "_id" : 3, "name" : "wangwu", "age" : 30 }{ "_id" : 4, "name" : "zhaoliu", "age" : 28 }{ "_id" : 5, "name" : "qianliu", "age" : 33 }{ "_id" : 6, "name" : "sunba", "age" : 32 } $type:鍵是某種類型的
double:1
string:2
...
> db.student.insert({_id:7, name:7, age:70})WriteResult({ "nInserted" : 1 })> db.student.find({name: {$type: 2}}){ "_id" : 1, "name" : "zhangsan", "age" : 27, "sex" : 1 }{ "_id" : 2, "name" : "lisi", "age" : 27 }{ "_id" : 3, "name" : "wangwu", "age" : 30 }{ "_id" : 4, "name" : "zhaoliu", "age" : 28 }{ "_id" : 5, "name" : "qianliu", "age" : 33 }{ "_id" : 6, "name" : "sunba", "age" : 32 }> db.student.find({name: {$type: 1}}){ "_id" : 7, "name" : 7, "age" : 70 } 正則表達式
> db.student.find({name: /si/b/}){ "_id" : 2, "name" : "lisi", "age" : 27 } db.集合名稱.findOne({查詢條件},{指定鍵})
查詢出符合條件的第一條數據
> db.student.findOne(){ "_id" : 1, "name" : "zhangsan", "age" : 27, "sex" : 1 } db.集合名稱.find({查詢條件},{指定鍵}).limit(數字)
查詢前幾條數據
> db.student.find().limit(3){ "_id" : 1, "name" : "zhangsan", "age" : 27, "sex" : 1 }{ "_id" : 2, "name" : "lisi", "age" : 27 }{ "_id" : 3, "name" : "wangwu", "age" : 30 } db.集合名稱.find({查詢條件},{指定鍵}).skip(數字)
跳過前幾條數據
> db.student.find().skip(2){ "_id" : 3, "name" : "wangwu", "age" : 30 }{ "_id" : 4, "name" : "zhaoliu", "age" : 28 }{ "_id" : 5, "name" : "qianliu", "age" : 33 }{ "_id" : 6, "name" : "sunba", "age" : 32 }{ "_id" : 7, "name" : 7, "age" : 70 } 可以使用limit()和skip()實現分頁
> db.student.find().skip(0).limit(3){ "_id" : 1, "name" : "zhangsan", "age" : 27, "sex" : 1 }{ "_id" : 2, "name" : "lisi", "age" : 27 }{ "_id" : 3, "name" : "wangwu", "age" : 30 }> db.student.find().skip(3).limit(3){ "_id" : 4, "name" : "zhaoliu", "age" : 28 }{ "_id" : 5, "name" : "qianliu", "age" : 33 }{ "_id" : 6, "name" : "sunba", "age" : 32 }> db.student.find().skip(6).limit(3){ "_id" : 7, "name" : 7, "age" : 70 } db.集合名稱.find().sort({鍵:數字})
數字為1表示升序，數字為2表示降序
> db.student.find().sort({age:1}){ "_id" : 1, "name" : "zhangsan", "age" : 27, "sex" : 1 }{ "_id" : 2, "name" : "lisi", "age" : 27 }{ "_id" : 4, "name" : "zhaoliu", "age" : 28 }{ "_id" : 3, "name" : "wangwu", "age" : 30 }{ "_id" : 6, "name" : "sunba", "age" : 32 }{ "_id" : 5, "name" : "qianliu", "age" : 33 }{ "_id" : 7, "name" : 7, "age" : 70 }> db.student.find().sort({age:1, _id:-1}){ "_id" : 2, "name" : "lisi", "age" : 27 }{ "_id" : 1, "name" : "zhangsan", "age" : 27, "sex" : 1 }{ "_id" : 4, "name" : "zhaoliu", "age" : 28 }{ "_id" : 3, "name" : "wangwu", "age" : 30 }{ "_id" : 6, "name" : "sunba", "age" : 32 }{ "_id" : 5, "name" : "qianliu", "age" : 33 }{ "_id" : 7, "name" : 7, "age" : 70 } 以上內容是小編給大家介紹的MongoDB快速入門筆記(四)之MongoDB查詢文檔操作實例代碼，希望對大家有所幫助！
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