MongoDB is an is a cross-platform open-source document database, and the leading NoSQL database. Written in C, C++ and Java script .
1. Document-Oriented Storage »
JSON-style documents with dynamic schemas offer simplicity and power.
2. Ad hoc queries
3. Full Index Support »
Index on any attribute, just like you’re used to.
4. Replication & High Availability »
Mirror across LANs and WANs for scale and peace of mind.
MongoDB provides high availability with replica sets. A replica set consists of two or more copies of the data. Each replica set member may act in the role of primary or secondary replica at any time. The primary replica performs all writes and reads by default. Secondary replicas maintain a copy of the data on the primary using built-in replication. When a primary replica fails, the replica set automatically conducts an election process to determine which secondary should become the primary. Secondaries can also perform read operations, but the data is eventually consistent by default.
MongoDB scales horizontally using sharding. The user chooses a shard key, which determines how the data in a collection will be distributed. The data is split into ranges (based on the shard key) and distributed across multiple shards. (A shard is a master with one or more slaves.)MongoDB can run over multiple servers, balancing the load and/or duplicating data to keep the system up and running in case of hardware failure. Automatic configuration is easy to deploy, and new machines can be added to a running database.
5. Auto-Sharding »
Scale horizontally without compromising functionality.
6. Querying »
Rich, document-based queries.
7. Fast In-Place Updates »
Atomic modifiers for contention-free performance.
8. Map/Reduce »
Flexible aggregation and data processing.
MapReduce can be used for batch processing of data and aggregation operations. The aggregation framework enables users to obtain the kind of results for which the SQLGROUP BY clause is used.
9. GridFS »
Store files of any size without complicating your stack.