Comparison of SQL Server file database and relational database _mssql

Absrtact: With the development of application field and multimedia technology, people find many limitations and shortages of relational database, so database technology has entered the era of "post-relational database". The file database was born. In this paper, the similarities and differences of file database and relational database are compared from three aspects of data format, database structure and Web publishing data, and the difference between file database and file system of storing data in the past is different.

Keywords: database Internet file database Web database server

I. Advantages of relational databases and current problems

Since the end of the 60, the database technology has experienced the level database, the network database and the relational database to enter the database management system (DBMS) stage, the database technology research has made progress unceasingly. In the 80 's, relational databases became the mainstream of development, and almost all newly introduced DBMS products were relational. Relational database is an important milestone in the development of computer data management, which has the advantages of data structure, minimum redundancy, high program and data independence, easy to expand, easy to compile application and so on, and the larger information system is based on the design of structured database.
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 increasing. Since the development of relational database from 1970 to now, although the function is more perfect, but the processing of data types is limited to numbers, characters and so on, the processing of multimedia information only stays in the storage of simple binary code files. However, with the improvement of users ' application requirements, the development of hardware technology and the colorful multimedia communication method provided by Intranet/internet, the user's demand for multimedia processing has risen from simple storage to recognition, retrieval and deep processing, and it is the user who calls out "general" The database server deals with complex data types such as sounds, images, time series signals, and videos that account for 70% of the total amount of information. According to the data, in 1996, the global database market sales of nearly 4 billion U.S. dollars, is expected to 2000, the database market sales will reach 8 billion U.S. dollars. The huge growth potential comes from the processing needs of complex data types, making "hypermedia" databases dealing with complex data types the focus of investment research and development in various companies.

Ii. New concept of document data

Since 1989, Lotus has introduced a new concept of database technology-"file database", which differs from the traditional database, and is used to manage files, through its groupware product notes. In the traditional database, the information is divided into discrete data segments, and in the file database, the file is the basic unit of processing information. A file can be very long, very complex, unstructured, and similar to word processing files.
The file database is still in the database category, unlike the file system that cert manages the data. First, the files in the file system basically correspond to an application. When different applications need data that is part of the same, they must build their own files, not share the data, and the file database can share the same data. As a result, file systems are much more redundant than file database data, more wasteful of storage, and more difficult to manage maintenance. Second, the files in the file system are for a particular application, so it is very difficult to add new applications to the existing data, and the system is not easy to expand. Data and programs lack independence. The file database has the physical independence and logical independence of data, and the data and program are separated.
The file database is also different from the relational database, the relational database is highly structured, and the Notes file database allows you to create many different types of unstructured or free-form fields, and the main difference between relational databases is that he does not provide support for parameter integrity and distributed transactions. However, and relational databases are not mutually exclusive, they can exchange data between each other, thereby complementing and expanding.

iii. Similarities and differences between relational databases and document databases

Here are three ways to compare the similarities and differences between the two databases:
1. Format Text/Multimedia
In the information age, all information can generally be divided into two categories: a type of information can be represented by data or a unified structure. For example, costs, fees, personnel, wages, and employee performance can be described or expressed in numbers or words. This kind of information has the same hierarchy or network structure, which we call structured data, and another type of information cannot be represented by numbers or unified structures, such as images, sounds, etc., which we call unstructured data. These unstructured data can be either a piece of text information that contains a large amount of additional information (such as typesetting information), or a sound, image, or even an image. For the relationship between structured and unstructured data as shown in the figure, unstructured data includes structured data, but not just structured data; structured data belongs to unstructured data, a special case of unstructured data. Generally speaking, in people's understanding, the main characteristic of relational database is the structure of data. 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 increasing. Relational database is highly structured, this kind of data structure makes relational database have the least redundancy, high program and data independence, easy to expand, easy to compile application features. However, as the application field continues to expand, in order to meet the application of the data processing constantly "harsh" demand, people began to discover the many limitations of relational databases and deficiencies. Because the basic element of a file database is the file itself, and the files in the database can contain both structured and unstructured information, the file database is able to store and manage unstructured data like files. In particular, the Notes object library is a very good business information storage that can be used to efficiently store, propagate, distribute, and manage such information. Such information is usually rich in data types, such as tables (which can be obtained from a relational database or spreadsheet software), formatted text, www pages, images, OLE objects, or scanned images and faxes, audio or video signals such as multimedia information.
2, in the structure
relational database is the application of mathematical methods to deal with database data, its data model is also based on the mathematical concept, in the relationship model, the data in the user's view of the logical structure is a two-dimensional table. Lotus Notes is a file database management system, and the basic element of the file database is the file. The files here are similar to the records in the relational database. The structure of the notes file is defined by the form, and the form consists of a set of various field fields.
(1) Domain and fields (field)
In a relational database, domain is a collection of attribute values, such as a positive integer greater than 0 or less than 150, a collection of strings less than 25, and so on. In a file database, the concept of a field is present in a Form object, which is a single element of data stored on the form, and the domain determines what data a separate file can contain. Although the Chinese translations of the two are the same, their actual meaning and function are very different. Instead, the concept of the domain in the file database is similar to the field in the relational database.
(2) entry (item) and attributes (attribute)
In relational databases, there is the concept of attributes, that is, each column in a two-dimensional table is called an attribute, and a name for each column is the attribute name. In a file database, there is no "attribute", the file has an item, and an entry is any part of the data stored in the file. Each entry represents a piece of data in the file, and in the user interface, the entries in the file are displayed through the fields in the form. The two names are different, but I think it is easier to understand the meaning of entries in the file database from the perspective of "attribute".
(3) Views (view)
In relational and file databases, there is a concept of views. In a relational database, a view refers to a table that is exported from one or several basic tables (or views). Unlike a basic table, a view is a virtual table, where the data corresponding to the view is not actually stored in the database, and only the definition of the view is stored in the database (in the presence of a data dictionary). In the file database, the user browses the file through the notes view. A view is a very convenient directory in which users can see the profile and file status of a file, 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, the user can see a group of files of the key fields, and according to a certain criteria for the display of information classification and sorting. Essentially, the two logically resemble each other, that is, the data that the view corresponds to is not actually stored in the database, and only the definition of the view is stored in the database.
3. Web Database
In recent years, the network architecture has undergone a great change, the client/server structure is becoming more and more popular, the Intranet at an alarming speed in just one year quickly spread, facing a new pattern, how easy to achieve "client/server" connection and "Web/intranet" The connection becomes the focus of the database manager. With the development of computer and network technology, network-centric computing has been paid more and more attention, and WWW system and database have become the foundation of networked information service. If you can connect the file database to the WWW server, you can retrieve the files from the browser. This kind of integrated information network system: Database +www Server, it becomes the new domain of the next generation Internet research and development. Currently, a typical database application on the web should include three parts: a Web browser, an HTTP server, and a Web database server. For the general relational database, there are usually two methods to realize the application of Web database: The Web server provides middleware to connect the Web server and the database server, and the other is to download the application to the client directly to access the database. The most common middleware technologies are common Gateway Interface (CGI) and application programming interfaces (APIs). The CGI bug is that the CGI interface does not support continuous interoperability between users and databases, and that CGI is inefficient and needs to run multiple CGI programs at the same time. Each time the user connects to the server, the server creates a transaction or runs a copy of the CGI program. This can increase the burden on the server for a complex application or for multiple user access. API to a large extent to overcome the shortcomings of CGI, but its poor compatibility and research and development difficult to make the vast number of developers discouraged. Client Access database mainly includes Java script and Database Connector (IDC) and so on. Using Java Script and IDC to develop a Web database is simple but it also has some disadvantages, such as limited function and not fully controlling its process. So they are not competent for the development of more complex web databases. Isn't there a way to develop a relatively easy, powerful, and efficient Web database? Yes, the answer is-lotus Notes. Lotus Notes implements multimedia file management through a file database, and supports client/server working methods. Each data can contain several different forms of notes files. Stored on one or more notes servers, a database that many users can access is called a shared database. By taking advantage of security measures such as server access and database access control, database administrators can specify who can access the database and in what range of databases, and each database is synchronized via replication on the web. This enables users of file databases to access, track, store, and organize information on the network.
Four. Concluding remarks
In recent years, China's database market rapid development, and will have a greater potential for growth, performance as follows: First of all, in the last five years, the concept of user selection has undergone significant changes, more users to the importance of the database in a very important position, The main reason is that users will put application software and application requirements in the first place, whether the application software to meet user needs is the symbol of the success of the whole project, and application software research and development directly depends on the database development tools. In fact, a lot of potential investment is in the development of the application software, another reason is the hardware as the chip technology is increasingly lack of characteristics, hardware indicators will become a secondary consideration. For industry applications, the previous is to make several hardware products as the optimization, now may be the best choice of database manufacturers to consider hardware manufacturers. It is this change in user demand that gives database vendors new opportunities for development. Lotus Notes provides a powerful platform for database system integrators to research and development, combining the powerful technologies of enterprise-class email, Distributed file database and rapid application development, complete integration of Internet technology, providing users with complete, Network-centric technology platform. Can predict that in the near future, Lotus Notes file database will become a hierarchical database, network database and relational database after another hot technology.