Why use a database? Use a database.

Why use a database? Use a database.
Why databases?
1. file read/write, archive read data needs to read all the data at a time, occupying the memory
2. The efficiency of searching data in the database is very high. It is reflected in data search and data modification (addition, deletion, modification, and query)
Why Learning databases?

I feel that your teacher is a bit dumb. You can find answers to these questions in your database book or at the forefront of any database textbook.

Why Learning databases? Because of his importance, a database-free system is a dead system.
With the database, you have a life ~ Of course, it would be useless if you only want to make a static Web database.
However, the concept advocated by the network is interaction ~ What should we do if we need to communicate with each other? Store shells with databases.

When do I need to use a database? When you need to store information, such as dynamic websites and portal websites, some of their information is dynamic. At this time, databases are used. What is a database? It is easy to understand from the literal point of view, that is, a database that stores a large amount of data. You cannot put all the data on the interface. Of course, if you are interested in it, it is not too troublesome and do not consider security, you can store a large amount of information on the user interface or in a notepad file.

Why is database more important in the Internet era?
This problem is even easier. Because the network advocates interaction, databases must be used for interaction. The network is now evolving towards open interaction, in the future, it will no longer be what the website owner said. The network has been transformed into a communication platform, where each person can cut his head and only communicate on this platform. So what do you want to communicate? What if you exchange a large amount of information? It's easy to use databases for storage.

Why use a database?

When people describe this concept from different perspectives, there are different definitions (of course, descriptive ). For example, a database is called a "record storage system" (this definition emphasizes that a database is a collection of several records ). Another example is "a database is a collection of related data stored together in an organizational manner to solve specific tasks" (this definition focuses on data organizations ). What's more, the database is called "a data warehouse ". Of course, this statement is not rigorous although it is an image. Strictly speaking, databases are "warehouses that organize, store, and manage data according to the data structure ". In the daily work of economic management, it is often necessary to put some related data into such a "warehouse" and process the data according to the management needs. For example, an enterprise or a public institution's Personnel Department often stores the basic information of its employees (employee ID, name, age, gender, nationality, salary, and resume) in table 20176.3, this table can be viewed as a database. With this "Data Warehouse", we can query the basic information of a certain employee at any time as needed, as well as the number of employees with a certain wage range. If all these tasks can be performed automatically on the computer, then our personnel management can reach an extremely high level. In addition, a large number of such databases need to be established in financial management, warehouse management, and production management so that they can use computers to achieve automatic management of finance, warehouses, and production.

J. martin gave a complete definition to the database: the database is a collection of related data stored together. The data is structured and has no harmful or unnecessary redundancy, it also serves a variety of applications. Data Storage is independent of programs that use it. New data is inserted into the database, and the original data can be modified and retrieved in a public and controllable manner. When a system contains several fully separated databases, the system contains a "database set ".

? Database advantages

Using databases can bring many benefits, such as reducing data redundancy, greatly saving data storage space, and fully sharing data resources. In addition, the database technology also provides users with easy-to-use means to make it easy for users to write database applications. In particular, dBASELL, a micro-computer relational database management system launched in recent years, provides intuitive operations, flexible use, convenient programming, and a wide range of environments (generally sixteen-bit machines, such as IBM/PC/XT, great Wall 0520 in China can run various types of software), with strong data processing capabilities. Databases are becoming more and more widely used in China and will surely become a powerful tool for economic management.

Database is the database management system (DBMS-DATA base management system) software to achieve data storage, MANAGEMENT and use of dBASELL is a kind of database management system software.

? Database Structure and types

Databases are generally divided into hierarchical databases, network databases, and relational databases. Different databases are connected and organized according to different data structures.

1. Data Structure Model

(1) Data Structure

The so-called data structure refers to the organization form of the index data or the relationship between the data. If D is used to represent data and R is used to represent a set of relationships between data objects, DS = (D, R) is called a data structure. For example, you have a telephone number book that records the names and numbers of n people. To conveniently search for a person's phone number, sort the person's name and number in alphabetical order and follow the corresponding phone number behind the name. In this way, to find a person's phone number (assuming that the first letter of his name is Y), you only need to find the names starting with Y. In this example, the data set D is the person name and phone number, and the relationship R between them is arranged in alphabetical order. The corresponding data structure is DS = (D, R ), it is an array.

(2) Data Structure Types

The data structure is divided into the logical structure of the data and the physical structure of the data. The logical structure of data is to observe and analyze data from a logical perspective (that is, the relationship between data and the organization mode), regardless of the data storage location. The full text of the data...>