how to query mongodb in java

Mongodb uses fuzzy search and $ type for recent monitoring services. Because non-numeric data is collected, the monitoring charts cannot be displayed normally. Therefore, you need to find and delete the data, the developer then corrects the data inserted into the database from the source and no longer produces non-numeric content. The following is an example: Create test data: for (i1; i100; I ++ Mongodb us

of a lot of data count is 1,that is {"match": {"Count": {"GT": 2}}; failure, why?4, back up the first before deleting.Backup /usr/local/mongodb/mongodb-linux-x86_64-2.4.4--30000-d-c paymentinfo -o /home/backup/mongodb_pos_paymentinfo_3.txt5, start loop DeleteHere DS is a large result set, directly with Ds.result can get the result set inside the packet query ou

Apsaradb for MongoDB 2.4 and later versions are more user-friendly for space query.$ GeoWithin, translated from: http://docs.mongodb.org/manual/reference/operator/geoWithin/#op._S_geoWithin $ Geowithin Use in mongodb2.4$ GeoWithinThe operator (or function, also the same as below) replaces the discarded$Operator.$ GeoWithinAn operator is another specific point, line, or other geometric element that supports

In many cases, some slow queries cause a lot of pressure on MongoDB. It took some time to write a script and kill some slow query operations. Var j = 0; Var _ DEF_TIME = 10;// Set the slow query time For(Var I in db. currentOP (). inprog ){ Var op =""; Var opid; Var memProg = {} If(Typeof (undefined) = typeof (db. currentOP (). inprog [I])

Many times, some slow queries cause MongoDB pressure, and it took a while to write a script loop to kill some slow query operations The code is as follows Copy Code var j = 0;var _def_time = 10; Set slow query timefor (Var i in Db.currentop (). InProg) {var op = "";var opid;var Memprog = {}if (typeof (undefined) = = typeof (Db.current

Db. Collection name. Find ({condition}). Count () can also be associated with a Db. Collection name. Count ({condition})　　 Example 1: Statistics on the number of males Db.stu.find ({gender:1}). Count ()　　 Example 2: Number of males with a statistical age greater than 20 Db.stu.count ({age:{$gt: 20},gender:1})　　5. Eliminate duplication Method Distinct () to de-weight the data Grammar Db. Collection name. Distinct (' Redo field ', {

the PRINT statement to print out the object information returned by the above statement, further verifying that the return value is as we guessed. Here userid This field is originally a document name in the collection, which is understood as a field name in a table. This is equivalent to the property of an object. *///loop with anything, as long as you can control the number of times, do not because the data volume is too large to cause the operation failed. for (info = Db.info.findOne ({"useri

Query.all ("name", "a", "B");//match array with multiple elementsQuery.and (Query.eq ("name", "a"), Query.eq ("title", "T"));//satisfy multiple conditions at the same timeQuery.eq ("name", "a");//equalsQuery.exists ("type", true);//Determine if key value existsQUERY.GT ("value", 2);//Greater Than >Query.gte ("Value", 3);//greater than or equal to >=Query.in ("name", "a", "B");//Includes all values specified, you can specify different types of conditions and valuesquery.lt ("value", 9);//Less tha

After reading some information, I only need to know how to query and use MongoDB. This is enough. On the left is the MongoDB query statement, and on the right is the SQL statement. It is easy to use. DB. Users. Find () Select * from users DB. Users. Find ({"Age": 27}) Select * from users where age = 27 DB. Users. Find

Label:Read some information, corresponding only need to know how to query and use MongoDB for me, these are enough. On the left is the MONGODB query statement, and the right is the SQL statement. Compared with the use, very convenient. Db.users.find () SELECT * from Users Db.users.find ({"Age": +}) SELECT * from the us

Tags: JSON it's equality function database query collection size block MONGO3.4.2 Data Query In the MongoDB database, the support for database queries is in place, with relational operations, logical operations, array operations, and regular operations. For the query operation core syntax for data: Db. Collec

Mongodb Study Notes 03 -- query expressionMongodb Study Notes 03-query expression Not equal to, greater than, less! =: Db. stu. find ({name: {$ ne: 'billvsme '}) name is not 'billvsme'>: db. stu. find ({age: {$ gt: 18}) older than 18 In/not in/all$ In: db. goods. find (stu_id: {$ in: [93001,93002, 93003]}) Student ID 93001, 93002, or 93003 $ nin: not in $ all: th

Query records Common Query > Var cursor = dB. Things. Find (); > While (cursor. hasnext () printjson (cursor. Next ());The above example shows the cursor-style iterative output. The hasnext () function tells us whether there is any data. If so, you can call the next () function. When we use JavaScript shell, we can use the JS features, and foreach can output the cursor. the following example uses foreach (

; var now = Math.floor ((New Date (). GetTime ())/$)//seconds since epoch right no W > Db.oplog.rs.find ({"TS": {"$lt": Timestamp (now, 1), "$GT": Timestamp (Now-secs_per_hour, 1)}}Query for Oplog within a certain time period (of course, note that UTC is stored)> var since = Math.floor (Isodate ("2014-08-12t09:00:00.000z"). GetTime ()/+) > var until = Math.floor ( Isodate ("2014-08-12t15:00:00.000z"). GetTime ()/ > Db.oplog.rs.find ({"TS": {"$lt": Tim

": "Smells like Teen Spirit", "Tracklist.track": "1"})System returns:{"_id": ObjectId ("5aa4912953350e04ddbd6fa7"), "Type": "CD", "Artist": "Nirvana", "Title": "Nevermind", "tracklist": [{' track ': ' 1 ', ' title ': ' Smells like Teen Spirit ', ' Length ': ' 5:02 '}, {' track ': ' 2 ', ' title ': ' In Bloom ', ' lengt H ":" 4:15 "}]}{"_id": ObjectId ("5aa49fe653350e04ddbd6fac"), "Type": "CD", "Artist": "Nirvana", "Title": "Nirvana", "tracklist": [ {' track ': ' 1 ', ' title ': ' You Know ' is r

: ' $lastModifyByUserCode ', createtime: ' $createTime '}}}) Show additional fields (must use aggregation [$sum, $avg, $first, $last, $max, $min, $push, $addToSet, $stdDevPop, $stdDevSamp]) Db.test.aggregate ({' $group ': {' _id ': ' $lastModifyByUserCode ', ' count ': {' $sum ': 1}, ' Createtime ': {' $first ': ' $ Createtime "}}}) Cast, you can rename the field to create a copy of the field (note: When renaming a field, MongoDB does not record the

One of the biggest features of MongoDB is that it supports dynamic queries, just like traditional relational database queries, but its queries come in more flexible mode. One, query Expression Objects: Querying an Expression object The query expression document is also a Bson structure document, for example, we can use the following

Related data is stored together, and targeted queries can eliminate join, which is more efficient and convenient than distributed storage. Related data is stored together, and targeted queries can eliminate join, which is more efficient and convenient than distributed storage. MongoDB intermediate ----> join multi-Table query [Date: 2011-08-19] Source: Linux Author: crazyjixiang [Font:] DBRef i

From:http://stackoverflow.com/questions/12629692/querying-an-array-of-arrays-in-mongodbDataDb.multiArr.insert ({"id": "fruit1", "Keys": [["Apple", "carrot", "banana"]]}) Db.multiArr.insert ({"id": "Fruit2", " Keys ": [[" Apple "," orange "," Banana "]]}) db.multiArr.find ({' Keys ': {$elemMatch: {$elemMatch: {$in: [' Carrot '}}}}) {" _ ID ": ObjectId (" 506555212AEB79B5F7374CBF ")," id ":" fruit1 "," Keys ": [[" Apple "," carrot "," banana "]]}db.multiarr.fin D ({' Keys ': {$elemMatch: {$elemMat

Show DBS: Displays all local databases. That is, the local MongoDB database, which holds all databases under the folder of the database. Use TestDB: Using the TestDB database. This is the only way to use show collections, db. Userinfo.find ({}). Pretty (), DB. Userinfo.findone () command, otherwise you will not be sure of the database that is queried.Show Collections: Displays all the collections and collection in the specified database.Db. Userinfo.f