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The editor will share with you what kinds of databases there are. I hope you will gain a lot after reading this article. Let's discuss it together.

Database types can be divided into hierarchical type, network type and relational type. The hierarchical database presents the data according to the hierarchical structure (tree structure); the mesh database adopts the network principle and method and is based on the network data model; the relational database refers to the database that uses the relational model to organize the data.

What are the types of databases?

In the early days, there are three kinds of popular databases, namely, hierarchical database, mesh database and relational database. In today's Internet, there are two most common types of databases, namely, relational databases and non-relational databases.

Introduction of hierarchical database

Hierarchical database is the first database system software developed, which presents the data according to the method of hierarchical structure (tree structure). Hierarchical database used to be a very popular database, but with the gradual popularity of relational database, it is seldom used now.

Characteristics: the nature of the tree determines the characteristics of the tree data model

1. There is one and only one node in the whole model that does not have a parent node, and the rest of the nodes must have one and only one parent node, but all nodes may not have child nodes

two。 All child nodes cannot exist separately from the parent node, that is, if you want to delete the parent node, all the child nodes under the parent node should be deleted at the same time, but some leaf nodes can be deleted separately.

3. Each record type has one and only one path from the parent node to itself

The more symbolic hierarchical database is the IMS (Information Management System) database, which is developed by IBM.

Introduction to reticulated database

Definition: a data structure model that uses a directed graph to represent the relationship between entities is called a mesh data model.

Characteristics:

1. There can be two or more nodes without a parent node

two。 Allow more than one parent node to exist on a single node

Detailed introduction of Relational Database

Network database and hierarchical database are lack of data independence and abstractness. When users carry out storage, they need to declare the storage structure and relative path of the data. The relational database can solve this problem more practically.

Relational database refers to a database that uses a relational model to organize data, which stores data in the form of rows and columns for users to understand. A series of rows and columns in a relational database are called tables, and a group of tables make up the database. The user retrieves the data in the database through a query, which is an execution code that defines certain areas of the database. The relational model can be simply understood as a two-dimensional table model, and a relational database is a data organization composed of two-dimensional tables and their relationships.

Like Excel workbooks, relational databases use two-dimensional tables made up of columns and rows to manage data, which is easy to understand. In addition, it also uses SQL (Structured Query Language, structured query language) to perform practical operations on the data.

Detailed introduction of non-relational database

With the rise of Internet technology Web2.0, traditional relational databases have been unable to cope with large amounts of data, such as large-scale and high concurrency Weibo, Wechat or SNS type web2.0 dynamic web pages, and exposed many insurmountable problems. Therefore, for large-scale data scenarios, there is a database product-NOSQL database for the purpose of excellent performance and convenient application.

Non-relational database is mainly based on "non-relational entity model" database, also known as NoSQL database. The original meaning of NOSQL is "Not only SQL", not the meaning of "NoSQL". Therefore, the emergence of NoSQL is not to completely deny the relational database, but as a reasonable supplement to the traditional relational database. NOSQL database can give full play to unimaginable high efficiency and excellent performance in special situations.

Non-relational databases can also be subdivided into four small items:

Key value (Key-Value) storage database

Column Storage (Column-oriedted) database

Text document oriented (Document-Oriented) database

Pattern (Graph) database.

Differences in the application fields of different kinds of databases

From the point of view of database application, the database can also be divided into operation-oriented and data analysis-oriented. The following is a brief introduction to the database according to the actual application scenarios.

1. Operation-oriented relational database

Typical applications: ERP,CRM, credit card transactions, small and medium-sized e-commerce

Data storage method: table

Popular vendors: Oracle Database,Microsoft SQLServer,IBM DB2,EnterpriseDB (PostgreSQL), MySQL

Advantages: perfect eco-environmental protection, transaction assurance / data consistency

Disadvantages: stringent data model definition, database expansion restrictions, and non-structural combination of applications are difficult.

two。 Relational database for data analysis

Typical application areas: data warehouse, business intelligence, data science research

Data storage method: table

Popular manufacturer: Oracle Exadata,Oracle Hyperion,Teradata,IBM Netezza,Google BigQuery

Advantages: consistency of information content and calculation

Disadvantages: must be maintained by IT staff who specialize in database technology, and the corresponding data are usually minutes.

3. Operation-oriented non-relational database

Typical application field: Web,mobile,and IoT applications,social networking,user recommendations,shopping carts

Data storage method: there are many storage structures (document,graph,column,key-value,time series)

Popular manufacturer: MongoDB,Amazon DynamoDB,Amazon,Redis

Advantages: convenience, coordination capability (without predefined methods), horizontal scaling (adapting to large amounts of data), and low cost (open source systems)

Disadvantages: lack of transaction assurance

4. Non-relational database for data analysis

Typical applications: indexing millions of data points, predictive analysis, fraud testing

Data storage method: Hadoop does not need the original data structure; data can be stored across several servers

Popular manufacturer: Cloudera,Hortonworks,MapR,MarkLogic,Snowflake,DataBricks,ElasticSearch

Advantages: suitable for batch processing, parallel processing of files; mainly open source, low capital investment

Disadvantages: slow response speed; not suitable for rapid retrieval or high-speed update

After reading this article, I believe you have a certain understanding of the types of databases, want to know more related knowledge, welcome to follow the industry information channel, thank you for reading!

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