First, the application field of SQL database
1, multimedia database
This database mainly stores data related to multimedia, such as voice, image and video data. The biggest characteristics of multimedia data are continuous data, large amount of data and large storage space.
2. Mobile database
The database is developed on mobile computer systems such as notebook computers and palmtop computers. The biggest feature of database is transmission through wireless digital communication network. Mobile database can obtain and access data anytime and anywhere, which brings great convenience to some business applications and some emergencies.
3. Spatial database
At present, this kind of database is developing rapidly. It mainly includes geographic information database (also called GIS) and computer aided design (CAD) database. Among them, geographic information database generally stores information data related to maps; CAD database is generally a spatial database for storing design information such as design drawings of machinery, integrated circuits and electronic equipment.
4. Information retrieval system
Information retrieval is to find relevant documents or information from the database according to the information input by users and feed back the information to users. The fields of information retrieval and database are developing simultaneously. It is a typical online document management system or online book catalogue.
5. Distributed information retrieval
With the development of Internet, this kind of database came into being. It is widely used in Internet and remote computer network system. Especially with the development of e-commerce, this kind of database develops more rapidly. Many network users (such as individuals, companies or enterprises) store information in their own computers.
6. Expert decision-making system
Expert decision system is also a part of database application. Because more and more data can be obtained online, especially through these data, enterprises can make better decisions on the development of enterprises and let enterprises operate better. With the development of artificial intelligence, the application of expert decision system is more and more extensive.
Second, the status quo of SQL database
1, independently developed.
Domestic enterprises and units that independently research and develop relational databases basically originated in the 1990s, and most of them are universities and scientific research institutions. Today's representative manufacturers are: Damon-founded by Professor Feng Yucai of Huazhong University of Science and Technology, completely independent research and development. Take Oracle Bone Inscriptions as a reference and catch up with the target.
2. Introduce the source code
Introduce database source code to develop domestic databases. Now, the economy is developing, and IBM is willing to cater to the demands of Chinese people for localization, and take out Informix source code that has been shelved for many years to give full play to the waste heat. Since 20 15, companies that have signed source code licenses with IBM include Huasheng Tiancheng, Nanda General Motors (Gbase8t) and Xingruige. These three companies have become representatives of developing domestic databases by introducing Informix source code.
Third, the development prospect of SQL database
1, product serialization
On the one hand, with the rise of Web, data warehouse and other applications, the absolute amount of data is expanding rapidly at an alarming rate; On the other hand, mobile and embedded applications are growing rapidly. According to the different needs of the market, the database is developing in the direction of serialization.
2. Intelligent integration
The extensive use of SQL database technology has collected and accumulated a lot of data for enterprises and organizations. The reality of rich data and poor knowledge directly led to the emergence of on-line analytical processing (OLAP) and data mining technologies, which promoted the development of intelligent database.
3. Support various Internet applications.
SQL database management system is one of the important infrastructures of network economy. Supporting Internet (even mobile Internet) database application has become an important aspect of database system. For example, Oracle has fully supported Internet applications since Version 8, and is the representative of Internet database.
Extended data:
SQL includes all operations on the database, which is mainly composed of four parts:
1. Data definition: also known as "DDL language", it defines the logical structure of the database, including defining the database, basic tables, views and indexes.
2. Data operation: also known as "DML language", including three operations: insert, delete and update.
3. Data query: also known as "DQL language", including data query operation.
4. Data control: also known as "DCL language", the control of users' access to data has the authorization and recovery of basic tables and views.
5. Transaction control: also known as "TCL language", including transaction submission and rollback.
Baidu encyclopedia -SQL database