MongoDB的基本操作

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MongoDB的基本操作有：添加 刪除 更新 和 讀取

啟動MongoDB Shell：命令列輸入mongo（Centos 7）

[[email protected] test]# mongoMongoDB shell version: 2.6.12connecting to: testServer has startup warnings: 2017-08-31T17:54:18.621+0800 [initandlisten] 2017-08-31T17:54:18.621+0800 [initandlisten] ** WARNING: Readahead for /var/lib/mongodb is set to 4096KB2017-08-31T17:54:18.621+0800 [initandlisten] **          We suggest setting it to 256KB (512 sectors) or less2017-08-31T17:54:18.621+0800 [initandlisten] **          http://dochub.mongodb.org/core/readahead> 

添加文檔：

> db.test.insert({"key_a":"value_a"})WriteResult({ "nInserted" : 1 })> db.test.insert({"key_b":"value_b"})WriteResult({ "nInserted" : 1 })

 

讀取文檔：

find()可查詢多個合格文檔，findOne()只查詢一個，

> db.test.find(){ "_id" : ObjectId("5a12da411c97109757a27d5d"), "key_a" : "value_a" }{ "_id" : ObjectId("5a12dab51c97109757a27d5e"), "key_b" : "value_b" }

> db.test.findOne(){ "_id" : ObjectId("5a12da411c97109757a27d5d"), "key_a" : "value_a" }

> db.test.findOne({"key_b" : "value_b"}){ "_id" : ObjectId("5a12dab51c97109757a27d5e"), "key_b" : "value_b" }> db.test.findOne({"_id" : ObjectId("5a12da411c97109757a27d5d")}){ "_id" : ObjectId("5a12da411c97109757a27d5d"), "key_a" : "value_a" }

更新文檔：

> db.test.insert({"key_c":"value_c"})WriteResult({ "nInserted" : 1 })
> db.test.findOne({"key_c" : "value_c"}){ "_id" : ObjectId("5a12e0a38710e2c2442eda15"), "key_c" : "value_c" }
> db.test.update(db.test.findOne({"key_c":"value_c"}),  {"new_key_c" : "new_value_c","key_c" : "value_c"})WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.test.findOne({"key_c":"value_c"}){    "_id" : ObjectId("5a12e0a38710e2c2442eda15"),    "new_key_c" : "new_value_c",    "key_c" : "value_c"}

刪除文檔：

> db.test.remove({"key_c":"value_c"})WriteResult({ "nRemoved" : 1 })> db.test.findOne({"key_c":"value_c"})null

 

MongoDB的基本操作