Database management system
A database is a specific set of data that is typically linked by a unifying feature or property (or several). These data are ordered, for example, alphabetically. The abundance of different data that can be put into a single database leads to many variations of what can be recorded: user personal data, records, dates, orders and so on. For example, if you have an online store, the database of your site may contain price lists, catalog of goods or services, reports, statistics and customer information.
First of all, it is convenient because the information can be quickly recorded in the database and as quickly as possible to extract it if necessary. If at the dawn of web-development all the necessary data had to be written in the code of the page, now there is no such need - the necessary information can be requested from the database using scripts. Special algorithms for storage and retrieval of information used in databases, allow you to find the right information in just a fraction of a second - and when working in virtual space resource speed is important as nothing else.
The relationship of information in the database is also important: changing one line can lead to significant changes in other lines. Working with data in this way is much easier and quicker than if the changes touched only one place in the database.
However, this does not mean that the database must be at every site - for example, if you have a business card site, and no new information you do not place on the site, the database you will simply not need.As you can guess from the name, database management system (or DBMS for short) is a software that is used to create and work with databases. The main function of the DBMS is data management (which can be both in external and RAM). DBMS necessarily supports database languages and is also responsible for copying and restoring data after any failures.
As far as the database classification is concerned, there are various options.
For example, you can divide the databases by model: hierarchical (have a tree structure), network (similar in structure to the hierarchical), relational (used to manage relational databases), object-oriented (used for the object model of data) and object-oriented (some merger of relational and object-oriented type of databases).Or, if the division follows the DBMS location, they can be divided into local ones - the whole DBMS is located on one computer, and the distributed ones - the database management system parts are located on several computers.File-server, client-server and embedded - such names are given by the DBMS if they are divided by the database access method. At present the file-server DBMS is already considered obsolete; mainly the client-server systems (DBMS that are located on the server together with the database itself) and embedded systems (that do not require a separate installation) are used.
The information stored sqlplus option in the databases is not limited to text or graphic files only - modern versions of the DBMS also support audio and video file formats.In this article I will focus on DBMS used for storing the information of various web resources.
Why do we need these DBMS? Apart from their main function - storing and systematizing a huge amount of information - they allow processing client queries quickly and how to optimize sql query providing fresh and up-to-date information.This also applies to the changes you make - instead of changing the information in each site file, you can change it in the database, and then each page will immediately display the correct information.