how to query mongodb in java

Label:Objective In the previous "Java MongoDB query (a) simple query" We have a simple look at the following query, but only those queries are not enough, but also need complex queries, this is described in this article. 1. Data structure Collection: Firstcollection Data con

Tips for using Java to implement MongoDB Regular Expression query: // Fuzzy searchPrivate BasicDBObject getLikeStr (String findStr ){Pattern pattern = Pattern. compile ("^. *" + findStr + ". * $", Pattern. CASE_INSENSITIVE );Return new BasicDBObject ("$ regex", pattern );} DBObject query = new BasicDBObject ();

Conditions similar to: a=5 or (a=2 and b>3)Basicdblist endlist = new Basicdblist ();Basicdbobject forceend = new Basicdbobject ();Forceend.put ("status", 5);Basicdblist condlist = new Basicdblist ();Basicdbobject autoend = new Basicdbobject ();Condlist.add (New Basicdbobject ("status", 2));Condlist.add (New Basicdbobject ("EndTime", New Basicdbobject ("$lt", New Date ()));Autoend.put ("$and", condlist);Endlist.add (Forceend);Endlist.add (Autoend);Basicdbobject.put ("$or", endlist);A compound

Look for a long time query Objectid method is wrong, with Mongovue can query out, but is using Java do not know how to query 1.mongovue Query mode: Copy Code code as follows: {"_id": ObjectId ("5326bfc0e6f780b21635248f")} 2. In the pure

()) {User user = new user (); User.parse (Find.next ()); SYSTEM.OUT.PRINTLN (user); }} public static void Main (string[] ArGS) {Userdao Userdao = new Userdao (); Userdao.query (); } Queryoperators class source code: Queryoperators.java/** * Copyright (C) 10gen Inc. * Licensed under the Apache License, Version 2.0 (the "License"); * You could not use this file, except in compliance with the License. * Obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * *

Label:The 3.x version of MongoDB's Java driver has a completely new design compared to 2.x, and there is a big difference between class libraries and usage methods. For example, replacing basicdbobject with document, using builders class to build Bson instead of direct input $ command and so on, this paper deals with the use of the common additions and deletions based on the 3.2 version. In order to avoid lengthy space, divided into additions and dele

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 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

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

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

),//Query the Name property New Basicdbobject ("Age", true),//Sort by age False,//Whether Delete, true means delete New Basicdbobject ("name", "ABC"),//modified value, change name to ABC true)); Queryall ();}MongoDB does not support federated queries, subqueries, which need to be done by ourselves in the program. The result set of the

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