mongodb query performance

Simple query: Use a custom Xxxrepository interface. (See Chapter 11th Springboot + mongodb (simple query)) Complex Queries : Building classes with mongotemplate and some query criteria (basicdblist, basicdbobject, criteria, etc.) 1, Application.properties1 #mongodb

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

don't think so]. Many people are getting bored with Spring. Yes, Spring is ambitious. He almost wants to monopolize everything in Java. There is no way I can't do without Spring, so that I don't need to learn any other frameworks. I have learned a lot about Spring, such as Spring Security, Spring Integration, and Spring Batch... Without inventing the wheel, he has already provided many programming scenarios. I have used those scenarios to solve many problems in my work and make my work very eff

BKJIA: Both MongoDB and CouchDB are document-oriented databases, both of which use JSON document formats. They are generally seen as NoSQL databases and are very fashionable nowadays, there are many commonalities, but the difference between the two is obvious when it comes to queries. CouchDB needs a predefined view which is essentially a JavaScript MapReduce function ), mongoDB supports dynamic queries, si

(! Stringutils.isempty (Studentreqvo.getname ())) {Pattern pattern = pattern.compile ("^.*" + studentreqvo.getname () + ". *$", pattern.case_insensitive);Criteria = Criteria.where ("name"). Regex (pattern);Operations.add (Aggregation.match (criteria));}if (null! = Studentreqvo.getsex ()) {Operations.add (Aggregation.match (Criteria.where ("sex"). Is (Studentreqvo.getsex ())));}Long totalcount = 0;Gets the total number of pages that are addedif (null! = Operations operations.size () > 0) {Aggre

Inserting more than one test data> for (i=1;i... db.blog.insert ({"title": I, "content": "MongoDB Test article. "," name ":" Liu "+i});... }Db.blog.list.find (). Limit ((). ForEach (function (data) {print ("title:" +data.title);}) Cyclic foreach usageDb.blog.findOne (); Fetch a piece of dataDb.blog.find (); take more than one dataDb.blog.remove (); Delete a data setDb.blog.drop (); Delete tableTo delete a database:1.use dbname2.db.dropdatabase ()The

The basic syntax for MongoDB conditional query. 1 query. all ("name", "A", "B"); // matches array 2 3 query with multiple elements. and (query. eq ("name", "A"), query. eq ("title", "T"); // meets multiple conditions at the same

[Root @ sunrise16 bin] #./mongo MongoDB shell version: 2.0.0 Insert a document with array elements Queries documents with a specified value in an array element. > Db. food. find ({"fruit": {"$ all": ["banana"]}) Queries documents that match the specified array. Make sure that the number and order must be exactly the same; otherwise, the number and order cannot be found. > Db. food. find ({"fruit": ["banana"]}) Queries documents whose array elem

, 8]}});Can query {name: ' David ', age:26, Age: [6, 8, 9]}But the query does not show {name: ' David ', age:26, Age: [6, 7, 9]}$exists determine if a field existsQuerying all records that exist in the age fieldDb.users.find ({age: {$exists: true}});Query all records that do not exist in the name fieldDb.users.find ({name: {$exists: false}});$ne Not equal toThe v

determine the speed of MongoDB query.Conclusion1. Li Yun's cloud host has made certain restrictions that result. Regardless of setting the system, the configuration of the database, all. Cannot break through. An order of magnitude of QPS.2. The number of client CPU cores determines the speed of MongoDB queries.3.tcp limit passed. Walk inside. Nets can be avoided.4.linux OS beats windows. So the

MongoDB Query Find(2012-01-05 11:38:10)reproduced Tags:it Category: MongoDB MongoDB Query FindSpecifies the key to return, specifying the desired key through the second parameter of Find or FindOne.> db.visithomepage.find ({},{"user_i

stack" trace of the root cause is available in the Apache tomcat/6.0.41 logs. In the view of exceptions, this is due to a MongoDB connection timeout. So, to MongoDB to find the reason. First on the MongoDB configuration file: Copy Code code as follows: mongodb.replica-set=192.98.12.242:30007,192.98.12.245:30007 mongodb.hostname=192.98.12