how to query mongodb in java

Tags: mongodbIn the last blog, there is three query condition to be described. In the blog, we'll continue to what we had leant in the last blog.1 $mod' $mod ' operation is able-make us-to-do simple mod operation, and is no need to use where sentence.\2. $ne, $in, $nin' $ne ' means not equal.' $in ' is same as key word ' in ' in relationship. $nin is opsitive to ' in '3. $or and $norDurning the mutiple conditions, then result would be is return that i

:" + users.findandmodify ("New Basicdbobject" ("Age", "page"), New Basicdbobject ("name", "ABC")); Print ("findandmodify:" + users.findandmodify ( New Basicdbobject ("Age", 28),//Querying age=28 data New Basicdbobject ("name", true),//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

example, querying ageDb.users.find ({age:{$lt: ()}) Db.users.find ({age:{$gt:()})Db.users.find ({age:{$lte:]}) Db.users.find ({age:{$gte:22}})1.3 The logical OR operator is represented using $or, and the format is{$or: [{For example, querying all the user age=21 or age=22Db.users.find ({$or: [{age:21},{age:22}]})1.4, the logic and operator use ",", or $and, the format is{$and: [{For example, the query name is "T1" and all the user age=21Db.users.find

I have been idle for a while recently, and I have been able to spend enough time studying code integration. Because there are too many linguistics, I gradually feel that it is meaningless. I learned a little from other groups using MongoDB. In view of this quick start, because the foundation is not very reliable, it will always be forgotten. Looking at the MongoDB authoritative guide, although it is in Engl

Java code www.2cto. commongoclient?clientnull; try {mongoclientnew?client (102.198.119.29, 27017); dbdb=client. getDB (syslog); set the Where condition Scheme ($ match, newBasicDBOb Java code www.2cto.com using client = null for MongoDB aggregation query; try {using client = new using client (102.198.119.29, 27017); DB

MongoDB query analysis ensures that our proposed indexes are valid and is an important tool for performance analysis of query statements.MongoDB query analysis commonly used functions are: explain () and hint (). Using Explain ()Explain operations provide query informa

first document data in the collection, this method returns only one document data,This approach applies to matching only one document at the time of your query, or you only care about the first piece of data Copy Code code as follows: $obj = $collection->findone (); Var_dump ($obj); ?> You will see the following results Copy Code code as follows: Array (5) { ["_id"]=> Object (mongoid) #6 (0) { } [' Name ']

We know that MongoDB is a kind of relational database, so its query method is very different from the standard Structured Query language SQL. But no matter how complicated a structure it is, when it passes through the developer's hands, it only becomes the structure that the customer wants. Today is about how to MongoDB