Keep in mind the common cmd commands of Mongo

Let's blow the water !!

The logical structure of the MongoDB architecture.

The logical structure of MongoDB is a hierarchical structure.

Mainly from:

Document, collection, and database. The logical structure is user-oriented. You can use MongoDB to develop applications.ProgramThe logical structure is used.

The document of MongoDB is equivalent to a row of records in a relational database.
Multiple documents form a collection, which is equivalent to a relational database table.
Multiple collections are logically organized together, that is, databases ).
One MongoDB instance supports multiple databases ).

The hierarchical structures of documents, collections, and databases are as follows:

> DB. Test. Find ({Province: "Japanese province" },{ City: "Tokyo City" },{ sex: "female "});

 

> DB. Test. ensureindex ({"name": 1}, {"name": "name_1", "unique": True, "background": true });