First knowledge of MongoDB

1.mongodb is a NoSQL document database that stores data in a format of Bson (an extension of JSON) that supports binary data storage, including big data videos, images, and so on.

2.mongodb is developed using C + +, the source code is fully open source and shareable.

3.mongodb mode is free, because the database is stored in a JSON document, in Java, dbcollection equivalent to a table in the Oracle database, the stored DBObject equivalent to a table in the Oracle database, a record, There are a lot of dbobject,dbobject in the Dbcollection. The JSON object set, which is free, can be different.

4.bson vs. JSON: Bson is an extended pattern of JSON, Bson based on JSON, but has its own advantages: traversal is faster (traversing JSON requires a scan match of JSON, while traversing Bson because Bson saves each element's length to the element's head, Just know the length of the element can quickly locate the matching element); The operation is simpler (for JSON, the data storage is classless, and when data bits increase or decrease, it is possible to shift the data space, while using Bson you can specify the type of the element, so that the data space shift will not occur when you increment and decrement the number of bits) Added additional data types, such as the byte array type, to store binary data.