mongodb relational database

main features of the Key-value database, even with extremely high concurrent read and write performance, Redis,tokyo Cabinet,flare is the representative of this class. Document-oriented database for massive data access: This type of database is characterized by the ability to quickly query data in massive amounts of data, typically for

database classification Because of the nature of the relational database itself, and the time is relatively short, therefore, do not want to relational database, there are several databases can unified Jiangshan, relational

Acid principles for relational database compliance (1) A Atomic nature: All operations in a transaction, either done or done, the success of the transaction is the success of all operations in the transaction, as long as one operation fails, the entire transaction fails and needs to be rolled back. (2) C Consistency: The database should always be in a consistent

concerned with the internal structure of a document . This allows the storage engine to directly support a level two index , allowing efficient querying of any field . The ability to support the nesting of documents enables the query language to have the ability to search for nested objects , and XQuery is an example. MongoDB implements similar functionality by supporting the specification of JSON field paths in queries.

Reprinted from: http://t.dbdao.com/archives/why-is-mongodb-wildly-popular.html "If you show me the code and don't let me understand the data structure, I'll be confused." If I knew the data structure, I would obviously no longer have to look at your code more often. "– Written by Eric Raymond in" the Cathedral and the Bazaar:musings on Linux and Open Source by an accidental revolutionary ", 1997 Language innovation The basic task of programming is to

following categories are mainly divided into: Key-value database for high-performance concurrency reading and writing: The main features of the Key-value database, even with extremely high concurrent read and write performance, Redis,tokyo Cabinet,flare is the representative of this class. Document-oriented database for massive data

high concurrent read and write performance, Redis,tokyo Cabinet,flare is the representative of this class. Document-oriented database for massive data access: This type of database is characterized by the ability to quickly query data in massive amounts of data, typically for MongoDB and COUCHDB Distributed

extremely high concurrent read and write performance, Redis,tokyo Cabinet,flare is the representative of this class. Document-oriented database for massive data access: This type of database is characterized by the ability to quickly query data in massive amounts of data, typically for MongoDB and COUCHDB Distributed

. Advantages: Easy to scatter data The relationship between the various data is the main reason for the name of the relational database, in order to join processing, the relational database has to store the data in the same server, which is not conducive to the spread of data, which is not good at the

Label: Database Paradigm when designing the relational database, we should design a reasonable relational database to conform to different specifications, and the different norm requirements are called different paradigms, and the higher paradigm

. Insert the document DB. Collection name. Insert ({property Name: Property value}) 8. Query Document: Db.book1.find () 9. Document deletion: Db.book1.remove ({"Name": "Tom"}) 10. Documentation Update: Db.book1.update ({},{}) 11. Create a Database Implicitly creating use DB Db.c.insert ({name: "DB"}) 12. Database Delete Db.dropdatabase () Db.dropdatabase () These are simple commands to share with y

that it is not limited to fixed structure, can reduce some time and space overhead. In this way, users can add the fields they need as needed, so that in order to get different information of the user, it is not necessary to query the multi-tables in the relational database. The query can be completed only by taking the corresponding value out of the ID. But the non-re