Comparison between file databases and relational databases

Comparison of file databases and relational databases Abstract: With the continuous expansion of application fields and multimedia technology, people have found many limitations and deficiencies in relational databases, so the database technology has entered the post-relational database era. The file database came into being. This document compares the number of files in terms of data format, database structure, and WEB publishing data.

Comparison of file databases and relational databases Abstract: With the continuous expansion of application fields and multimedia technology, people have found many limitations and deficiencies in relational databases, so the database technology has entered the post-relational database era. The file database came into being. This document compares the number of files in terms of data format, database structure, and WEB publishing data.

Comparison between file databases and relational databases

Abstract: With the continuous expansion of the application field and multimedia technology, people have found many limitations and deficiencies in relational databases. As a result, database technology has entered the "post-relational database era ". The file database came into being. This article compares the similarities and differences between file databases and relational databases in terms of data format, database structure, and WEB publishing data, the differences between the file database and the file system that used to store data are also different.

Keywords: Database Internet File database WEB Database Server

I. Advantages and current problems of relational databases

Since the end of 1960s, the database technology has gone through the hierarchical database, mesh database and relational database and has entered the database management system (DBMS) stage. So far, the research on the database technology has also made continuous progress. In 1980s, relational databases became the mainstream, and almost all new DBMS products were relational. Relational databases are an important milestone in the history of computer data management, this type of database has the advantages of Data structuring, minimum redundancy, high program and data independence, easy expansion, and easy application programming, currently, large information systems are built on the design of structured databases.

However, with the rapid development of network technology and software technology, especially the development of Internet and Intranet technology, the application of unstructured data is expanding. Since its development in 1970, relational databases have become more and more sophisticated, but the processing of data types is limited to numbers and characters, multimedia Information is only stored in simple binary code files. However, with the improvement of users' application requirements, the development of hardware technology, and the various multimedia communication methods provided by Intranet/Internet, users' Requirements for multimedia processing have increased from simple storage to recognition, retrieval, and deep processing, it is precisely the type of complex data that users call out a "universal" database server to process 70% of the total information, such as sound, images, time series signals, and videos. According to relevant data, in 1996, the sales in the global database market was close to $4 billion. By 2000, the sales in the database market is expected to reach $8 billion. The huge growth potential comes from the processing needs of complex data types, making the "hypermedia" database for processing complex data types the focus of companies to invest in R & D.

Ii. New file data concepts

Since 1989, Lotus has introduced a new concept of database technology through its Group Component Product Notes-"file database", which is different from other traditional databases and is used to manage files. In traditional databases, information is divided into discrete data segments. In File databases, files are the basic unit for processing information. A file can be very long, complex, and non-structured, similar to a word processing file.

Different from the file system used to manage data in May 1960s, the file database still belongs to the database category. First, the files in the file system basically correspond to an application. When some of the data required by different applications are the same, you must create your own files instead of sharing data, and the file database can share the same data. Therefore, the file system is more redundant than the file database data, which wastes storage space and is more difficult to manage and maintain. Secondly, files in the file system serve a specific application. Therefore, it is very difficult to add new applications to existing data, and the system is not easy to expand. Data and programs are not independent. The file database has the physical and logical independence of data, and the data and program are separated.

File databases are also different from relational databases. Relational databases are highly structured, while the file database of Notes allows the creation of many different types of unstructured or arbitrary format fields, the main difference with relational databases is that they do not support parameter integrity and distributed transactions, but they are not mutually exclusive with relational databases. They can exchange data with each other, to complement and expand each other.

Iii. Similarities and Differences Between Relational databases and file Databases

The similarities and differences between the two databases are compared in the following three aspects:

1. format text/multimedia

In the information age, all information can be divided into two types: one type of information can be expressed by data or a unified structure. For example, costs, expenses, personnel, wages, and employee performance can be described or expressed in numbers or words. This type of information has the same level or network structure, which is called structured data. Another type of information cannot be represented by numbers or unified structures, such as images and sounds, we call it unstructured data. These unstructured data can be text information that contains a large amount of additional information (such as typographical information), a piece of sound, image, or even an image. For the relationship between structured data and unstructured data, unstructured data includes structured data, but not only structured data. Structured Data is a special case of unstructured data. In general, the most important feature of relational databases is Data structuring. However, with the rapid development of network technology and software technology, especially the development of Internet and Intranet technology, the application of unstructured data is expanding. Relational databases are highly structured. This data structure makes relational databases have the lowest redundancy, high program and data independence, easy to expand, and easy to compile applications. However, with the continuous expansion of the application field, in order to meet the application's "demanding" requirements for data processing, people began to find many restrictions and deficiencies in relational databases. Because the basic element of the file database is the file itself, and the files in the database can contain both structured and unstructured information, the file database can store and manage unstructured data such as files. In particular, the object library of Notes is an excellent commercial information storage that can be used to efficiently store, disseminate, distribute, and manage such information. This type of information is usually rich in data types, such as tables (which can be obtained from a relational database or spreadsheet software) format multimedia information such as text, WWW pages, images, OLE objects, or scanned images and images, audio frequency, and video signals.

2. Structure

Relational databases use mathematical methods to process database data. The data model is also based on mathematical concepts. In a relational model, the logical structure of data in the user's opinion is a two-dimensional table. Lotus Notes is a file database management system. The basic element of a file database is files. The file here is similar to the record in the relational database. The structure of the Notes File is defined by form, and form is composed of a set of various field fields.

(1) Domain and Field)

In relational databases, Domain is a set of attribute values, such as a positive integer greater than 0 and less than 150, and a string set smaller than 25. In the file database, the Field concept shows that in the current form object, the Field is a single element of data stored on the form, and the Field determines what data an independent file can contain. Although the Chinese translations of the two are the same, their actual meanings and functions differ by a thousand miles. On the contrary, the concept of domain in the file database is similar to that in the relational database Field.

(2) Item and Attribute)

In relational databases, attributes are defined. Each column in the tables Table is called an Attribute and each column is named an Attribute. In the file database, there is no "attribute". The file contains items, which are any part of the data stored in the file. Each entry represents a piece of data in the file. On the user interface, the entries in the file are displayed through the fields in the form. Although the two are named differently, I believe that it is easier to understand the meaning of entries in the file database from the perspective of "attributes.

(3) View)

Both relational databases and file databases have a view concept. In a relational database, a view is a table exported from one or more basic tables (or views. Different from the basic table, a view is a virtual table, that is, the data of the view is not actually stored in the database, and only the view definition is stored in the database (in the data dictionary ). In the file database, you can browse files in the Notes view. A view is a very convenient directory where you can view the summary information about the file and the file status, and then access a specific Notes file. Files in the file database can display all or part of the content in the view. Through the view, you can view the key fields of a group of files, the displayed information can be classified and sorted according to a certain criterion. Essentially, the two are logically similar, that is, the data corresponding to the view is not actually stored in the database, and only the view definition is stored in the database.

3. WEB Database

In recent years, the network architecture has undergone major changes, and the Client/Server structure has become increasingly popular. The Intranet has rapidly spread in just one year at an astonishing speed and is facing a new pattern, how to easily achieve "Client/Server" connection and "Web/Intranet" connection has become the focus of database administrators. With the development of computer technology and network technology, network-centric computing is becoming more and more important. WWW systems and databases have become the basis of networked information services. If you can connect the file database to the WWW server, you can retrieve files from the browser. This integrated information network system: database + WWW server has become a new area of research and development for the next generation Internet. At present, a typical database application on the Web should include three parts: Web browser, HTTP server and Web database server. For general relational databases, there are usually two ways to implement Web database applications: one is that the Web server provides middleware to connect the Web server and the database server; the other is to download the application to the client and directly access the database. The most common middleware technologies include the Common Gateway Interface (CGI) and application programming interface (API. The CGI program has the disadvantage that the CGI interface does not support continuous interoperability between users and databases. In other words, CGI is inefficient and Multiple CGI programs need to be run at the same time. Each time a user connects to the server, the server creates a transaction or a copy of the CGI program. In this way, server load will be increased when a complex application or multiple users access the application. API overcomes CGI's shortcomings to a large extent, but its poor compatibility and difficulty in R & D also discouraged R & D personnel. Client Access to the database mainly includes Java Script and Database Connector (IDC. Although it is simple to develop Web databases using Java scripts and IDCs, it also has shortcomings such as limited functions and inability to fully control the process. Therefore, they are not competent for the development of complex Web databases. Isn't there a simple, powerful, and efficient method for developing Web databases? Yes. The answer is-Lotus Notes. Lotus Notes implements multimedia file management through the file database, and supports client/server operations. Each data can contain several different forms of Notes files. Databases stored on one or more Notes servers are shared databases that can be accessed by many users. By using security measures such as server access and database access control, the database administrator can determine who can access the database and where to use the database. databases can be synchronized online through the copy function. In this way, file database users can access, track, and store and organize information on the network.

Iv. Conclusion

In recent years, China's database market has developed rapidly and has a greater potential for growth. It has the following characteristics: first, in the past five years, the concept of user selection has undergone significant changes. More users put the importance of the database in a very important position. The main reason is that users put application software and application requirements first, whether the application software meets user needs is a sign of the success of the entire project, and application software R & D relies directly on Database R & D tools. In fact, a large amount of potential investment lies in the development of application software. Another reason is that hardware becomes a secondary factor as chip technology develops and lacks features. For industrial applications, several hardware products were previously used as the preferred choice. Now it may be the best choice for database manufacturers to consider hardware manufacturers. This change in user requirements gives database vendors new opportunities for development. Lotus Notes provides a powerful file database R & D platform for database system integrators, notes integrates the three-in-one powerful technologies such as enterprise-level email, distributed file database, and fast application R & D, fully integrated with Internet technology, and provides a complete network-centric application technology platform. It can be predicted that in the near future, the file database of Lotus Notes will become another hot technology after the hierarchical database, mesh database and relational database.

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