Một số câu lệnh cơ bản khi làm việc với mongoDB.

1. Tạo một database trong mongo: 
               
                    mongo>use databasename

2. Hiện thị tất cả các database trong mongo:

                   mongo>show dbs

3. Copy database này sang database kia

                   mongo>db.copyDatabase('existed_databasename','new_databasename');

4. Xóa 1 database trong mongo

                  mongo>use databasename
                  mongo>db.dropDatabase()

5. Restore databas với folder chưa database:

                  mongo>mongorestore --host mongodb1.example.net --port 3017 --username user --password pass /opt/backup/mongodump-2013-10-24

6.  Optimize server level: 

      -   Using 64 bit instance.

      -   Use XFS or EXT4

      -   EBS in RAID. RAID 0 or 10 for data. RAID 1 for configdb

      -   Snapshot regularly for backup.

      -   Turn off atime or diratime when you mount a volume.

      -   GridFS for large objects. (> 16M) 

      -   Raise file descriptor limits.

  

7. Optimize query performance: 

      - Create Indexes to Support Queries:

          Should be created indexes, because scanning index is much faster than scanning a collection.

      - Limit the Number of Query Results to Reduce Network Demand:

           Using : limit() method.

      - Use Projections to Return Only Necessary Data

          Only return fields which you need for better performance.

      - Use $hint to Select a Particular Index:

          Use $hint for to support performance testing, or on some queries where you must select a field or field included in several indexes. 

     - Use the Increment Operator to Perform Operations Server-Side:

        Use $inc operator to support performance testing, or on some queries where you must select a field or field included in several indexes.