Mongodb Multiple Collection Query

MongoDB company formerly known as 10gen, founded in 2007, in 2013 received a sum of 231 million U.S. dollars in financing, the company's market value has been increased to 1 billion U.S. dollar level, this height is well-known open source company Red Hat (founded in 1993) 20 's struggle results. High-performance, easy to expand has been the foothold of the MongoDB, while the specification of documents and interfaces to make it more popular with users, this point from the analysis of the results of Db-engines's score is not difficult to see-just 1 years, MongoDB finished the 7th ...

Recently MongoDB in hack news is frequently shot. Many people even claim to hate Mongodb,david Mytton on his blog to expose MongoDB many existing problems. But those who hate have a lot in common, as a comeback: Russell Smith brings a summary of years of work experience. Russell Smith has worked as an OPS and a large website scaling advisor and has helped Guardian, Experian and many other companies, MongoDB Lond ...

MongoDB is currently the best document-oriented free Open-source NoSQL database. If you are preparing to participate in a technical interview for the MongoDB NoSQL database, you might want to look at the following MongoDB NoSQL interview questions and answers. These MongoDB NoSQL interview questions cover the basic concepts of NoSQL databases, replication (Replication), fragmentation (Sharding), Transactions and locks, trace analysis Tools (Profiler), nuances, and logging features. Let's look at the following ...

"51CTO exclusive feature" 2010 should be remembered, because the SQL will die in the year. This year's relational database is on the go, and this year developers find that they don't need long, laborious construction columns or tables to store data. 2010 will be the starting year for a document database. Although the momentum has been going on for years, now is the age when more and more extensive document databases appear. From cloud-based Amazon to Google, a number of open-source tools, along with the birth of Couchdb and MongoDB. So what ...

2010 should be remembered because SQL will die this year. This year, the relational database is on the verge of falling, and this year developers found they no longer needed long, laborious columns or tables to store data. 2010 will be the starting year for document databases. Although this momentum has lasted for many years, it is now the era of more and broader document-based databases. From cloud-based Amazon to Google, a large number of open source tools, and the ensuing CouchDB and MongoDB. So what is MongoD ...

&http://www.aliyun.com/zixun/aggregation/37954.html ">nbsp;1.find MongoDB uses Find to query. The query is to return a subset of the files in the set. The child collection ranges from 0 documents to the entire collection. The first parameter of find determines which documents to return. The form is also a document that describes the details to be queried. The empty query document {} matches the entire contents of the collection. If you don't specify ...

"51CTO classic" I like MongoDB mainly because it is so simple and natural to use it in dynamic languages. So far, I've used it in two projects (Encode and SPARRW), although I'm very happy with the choice, but there are some problems I haven't noticed, and these problems have kept me scratching my scalp for hours. If you have more than one machine, and then allocate a few more machines for the database, then some problems can be solved, but my project is running on a single (virtual) server on the low flow w ...

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Serendip is a social music service, used as a http://www.aliyun.com/zixun/aggregation/10585.html "> Music sharing" between friends. Based on the "people to clustering" this reason, users have a great chance to find their favorite music friends. Serendip is built on AWS, using a stack that includes Scala (and some Java), Akka (for concurrency), play framework (for Web and API front-end ...).

While technology like http://www.aliyun.com/zixun/aggregation/13461.html ">mongodb,mapreduce" is seen as a hallmark of innovation, companies rely on sophisticated technologies such as SQL. 　　Mining important business models from these data becomes very difficult when the enterprise needs to collect more data formats, especially when new formats are not supported by SQL. When faced with such a problem, the market ...