mongodb query tool

Different query operators in MongoDB treat null values differently.The examples on this page with the Db.collection.find () method in the MONGO shell. To populate the users collection referenced in the examples, run the following in MONGO Shell:Db.users.insert ( [ {"_id":, "name": null}, {"_id": 901} ])Equality FilterThe {name:null} query matches do

Learning MongoDB 5: MongoDB query (array, embedded documentation) (2), mongodb embedded1. Introduction We introduced db in the previous article. collection. find () can be used to query conditions and specify fields returned by using the projection operator to omit this para

Mongodb fuzzy query tutorial, mongodb fuzzy queryUse the RockMongo client tool for fuzzy search {"Content": "$ regex": "123456 "}Fuzzy search in other cases Query contains XXX {Name:/xxx /} Query starts with XXX {Name:/^ xxx

Lesson 5 MongoDB Data Query (II): mongodb Data Query1. Course outlineThis course continues to explain MongoDB Data Query related content, including MongoDB cursor, fuzzy query, and use

Learning MongoDB 6: MongoDB query (cursor operation, cursor information) (3), mongodb cursorI. Introduction Db. collection. find () can be used to query based on conditions and specify fields returned using the projection operator to omit this parameter to return all fields

Lesson 4 MongoDB Data Query (1): mongodb Data Query1. Course outlineThis course mainly describes MongoDB Data Query related content, including the introduction and use of the find function, query operator introduction and use, emb

. getcollectionnames () {system. out. println ("collection name:" + name);} dbcollection users = dB. getcollection ("EMP"); // query all data in the Set dbcursor cur = users. find (); system. out. println ("record count:" + cur. count (); While (cur. hasnext () {dbobject object = cur. next (); system. out. println (object); // retrieve the data system of the object whose names are 'uname' and 'upwd. out. println ("uname:" + object. get ("uname") + "\

field, and just the bo NUS field in the documents in the points array. The _id field is returned by default.Db.users.find ({status: "A"}, {name:1, status:1, "Points.bonus": 1})The operation returns the following documents:{"_id": 2, "name": "Bob", "status": "A", "points": [{"Bonus": $}, {"Bonus": 12}]} {"_id": 3, "name": "Ahn", "status": "A", "points": [{"Bonus": 8}, {"Bonus": 20}]} {"_id": 6, "name": "abc", "Status": "A", "points": [{"Bonus": 8}, {"Bonus": 7}]}Project specific array Elements i

MongoDB Practice Notes for beginners-install, create databases, save and query data, and learn mongodb MongoDB is a scalable and High-Performance Distributed Document storage database written in C. It is designed to provide scalable and high-performance data storage solutions for web applications. It features high perf

Query the embedded document and query the normal document is exactly the same;For example:>db.post.find () { "_id" :objectid ("54ace1394ba07ed75df68f90"), "Name" :{ "FirstName" : "Joe", "LastName" : "Schome" }, " Age ":28}{" _id ":objectid (" 54ace14a4ba07ed75df68f91 " ), "name" :{ "FirstName" : "snail", "LastName" : "Yu" NBSP;}, "Age" :29}{ "_id" :objectid (" 54ace18d4ba07ed75df68f92 ")," name ":{" FirstN

"), "id" :8, "test8" NBSP;: 8}{ "_id" :objectid ("54a970901b5afd45354fd08c"), "id" :9, "Test9" :9}{ "_id" :objectid (" 54a9709c1b5afd45354fd08d ")," id ":10," test10 ":10} { "_id" :objectid ("54aa8a90652d8bdfa0566d34"), "id" :11, "test10" :11}>db.post.find ({"id": {$mod: [5,1]}}) { "_id" :objeCtId ("54a530c3ff0df3732bac1680"), "id" :1, "name" : "Joe", "Age" NBSP;: 30, "Comments" :[ "Test2", "Test9", "test5" ], "Sex" NBSP;: 1, "School" : "Marry" }{ "_id" :objectid (" 54a970351b5afd45354fd089 "),

; Db.post.find ({"id": +}) {"_id": ObjectId ("54AA97D794DCF31069B590CB"), "id": +, "fruit": ["apple", "Kumquat", "Orange", "fruit01"]} >Returns the first two values of an array> Db.post.find ({"id": 13},{"fruit": {$slice: 2}}) {"_id": ObjectId ("54AA97D794DCF31069B590CB"), "id": "Fruit":["Apple", "Kumquat"]} >Returns the latter two values of an array> Db.post.find ({"id": 13},{"fruit": {$slice: -2}}) {"_id": ObjectId ("54AA97D794DCF31069B590CB"), "id": "Fruit":["Orange", "fruit01"]} >Returns the

mongodb port is 27017. Enter http: // localhost: 27017/in the browser, for example: Change the port to 28017 to view more mongodb Management Information: http: // localhost: 28017/For example: III. Basic operations As it is an entry point, let's just talk about the addition, deletion, modification, and query of mongodb