MongoDB getting started

I. Basic Concepts

MongoDB is a high-performance, open-source, and non-pattern document-based database. It is currently the most popular NoSQL database product. It can be used in many scenarios to replace traditional relational databases or key/value storage methods. MongoDB is developed using C ++. The official website address of MongoDB is http://www.mongodb.org/. you can provide more detailed information here.

MongoDB is a product between relational databases and non-relational databases. It has the most abundant functions and features like relational databases. The supported data structure is very loose and is similar to the json bjson format. Therefore, it can store complicated data types. The biggest feature of MongoDB is that it supports a very powerful query language. Its syntax is a bit similar to an Object-Oriented Query Language. It can almost implement most of the functions similar to single-table queries in relational databases, it also supports data indexing. It is a set-oriented, free-of-charge document-type database.

Ii. Comparison

	MongoDB	Relational Database Service
Data Storage	Set-oriented	Relational table
Data Structure	Free mode	Relational table Relationship Mode
Transactions	Not Supported	Supported
Large data (video)	Good	Average
Large data volume query (more than 10 million records)	Good	Poor
Database Maintenance	Relatively simple	Relatively complex
Data and table relationship and structure browsing	Difficult	Simple
Data security	Poor	Good
Distributed	Good	Average
Query	Very flexible	Very powerful
Primary foreign key Association	Not Supported	Supported
Index	Supported	Supported
Stored Procedure	Supported	Supported

Iii. Comparison

1. Data Storage

MongoDB is a collection-oriented collection that contains multiple documents and supports object-type data storage. The concept of integration and documentation is similar to table and metadata in relational databases (row: that is, a row of data ). In addition, MongoDB is stored in the form of bson, while relational databases are stored in the form of two-dimensional relationships.

2. Data Structure

MongoDB provides flexible support for data structures, from horizontal to vertical. For example, the following data can be stored in the same collection:

① {"Name": "wangwu", "age": 25}

② {"Name": "lisi "}

③ {"State": "activated", "remark": "none "}

④ {"Name": 6, "age": "You guess "}

From the above example, we can see that the field can be dynamically increased or decreased (such as ① and ②) in the horizontal aspect, and the Field Data Type Hybrid storage (such as ① and ④) is supported in the vertical aspect ). In relational databases, this type of storage cannot be achieved.

3. Transactions

MongoDB itself does not support transaction processing and can only be ensured through program code.

4. Large Data

MongoDB not only supports structured data, but also supports the storage of unstructured data (such as audio, video, documents, XML, and HTML). Although relational databases support the storage of large data (such as videos, however, no matter in terms of storage efficiency or acquisition speed, MongoDB can use efficient binary to store large data.

5. query large data volumes

MongoDB can query more than 10 million data records at a very high speed. This is a major pain point in relational databases.

6. Database Maintenance

MongoDB is very simple in database backup and restoration, as well as data import and export operations. It can be completed with simple commands. It also supports master-slave mode and mutual replication between servers. The primary goal of replication is to provide redundancy and automatic failover, while relational databases are more complex in operation and difficult to get started.

7. Data and table relationship and structure browsing

Because MongoDB does not have a very good GUI client, it is very difficult and clumsy in data browsing and table relations and structure browsing. Relational databases have obvious advantages in this regard.

8. Data Security

MongoDB is relatively poor in data security. If you are slightly careful or improperly performing operations, it may easily cause data loss or data errors. Therefore, you must be very careful in data maintenance and operations. However, there are fewer concerns about relational databases in this regard.

9. Distributed

MongoDB is ideal for databases composed of dozens or hundreds of servers. Supports automatic sharding to support cloud-level scalability. The automatic sharding function supports horizontal database clusters and allows you to dynamically add additional machines. Relational databases are more difficult and complex in Distributed support and operations.

10. Query

The query statements of MongoDB are very different from those of relational SQL statements, or both of them have good performance. MongoDB is mainly reflected in the flexibility and ease of use, SQL is reflected in the comprehensive and powerful functions.

11. Primary foreign key Association

MongoDB does not support primary/foreign key Association, nor does it have a "constraint" concept.

12. Index

MongoDB also supports indexing.

13. Stored Procedure

MongoDB also supports stored procedures.

 

Iv. Summary

Through the comparison above, we can see that MongoDB is designed to sacrifice security, transactions, and structures in exchange for simplicity, efficiency, and flexibility. Therefore, both relational and non-relational databases have their applicability, the emergence of non-relational databases has provided us with an alternative path, thus providing us with great help in data maintenance and storage, making us more comfortable in software development, therefore, people who are traditional and conservative about relational databases can try to experience non-relational databases. Maybe you will be fascinated by them in the first place, mastering a non-relational database is also very beneficial for your future development.

So the introduction to MongoDB will come here first. I will give a systematic summary and introduction of the specific content of MongoDB in the future, hoping to help those who need it.