Databases and their types
The article describes the role of databases in modern realities and its definition. In addition, the types of databases and their classification based on the data storage structure are specified. MySQL as a reference database for storing data in the Internet space.
Even before the advent of information technology, people had a need for orderly storage of certain data. For convenience, they were divided on a certain basis, combined into groups, created a hierarchical representation and used many other methods.
With the development of computer technology and the Internet, most of the methods that were previously used in libraries and archives were taken as a basis for storing data on computers devices of any sort.
Database from the point of view of Informatics is the storage of information in an orderly manner, following a specific system pre-installed by the developer.
The following types of databases are distinguished by their structure:
A hierarchical database is a database in which data is stored and structured according to the principle of dividing elements into parent and child. The advantage of such databases is the ease of reading the requested information and its rapid provision to the user.
The computer is able to quickly navigate it. The hierarchical principle is taken as a basis in structuring files and folders in the Windows operating system, and the registry stores information about the parameters of certain applications in a structured hierarchical way.
All Internet resources are also built on a hierarchical basis, as when using it to navigate within the site is very easy.
As an example, we can cite a database in XML, which contains essays on the state of agriculture in the regions of Russia. In this case, the parent element will be the state, and then there will be a division into subjects and within the subjects, there will be its branching. In this case, from the top element to the bottom is strictly one line.
A network database is a modified hierarchical database. Its peculiarity lies in the fact that elements can be linked to each other in violation of the hierarchy. That is, a child element can have multiple parent folders at the same time.
In this case, an example is also an XML-based database.
This type of databases refers to their representation in the framework of two-dimensional tables. It has several columns in which such parameters as, for example, the type of input data (text, number, date, etc.) are set.
The table here is a way to store the data entered into it and is able to respond to any calls from the database. The main problem with relational databases is their proper design.
The following two factors should be considered during database design:
the database must be compact and contain no redundant components;
database processing should be simple.
The problem is that these factors often contradict each other. However, the database design is the most important point in the preparation of the database and further work with it. Only server administrators who have some experience should deal with it.
Large projects involve many tables, which can be more than a hundred. At the same time, it is impossible to do without them if a person deals with an important and complex project.
Before you create a table, you should create a chart or diagram that contains information about the types of information stored, as well as the type of data that is best suited for such purposes.
Database management system is a term that does not need to be deciphered. It is an embedded module or a full-fledged program that is able to work with data and make changes to databases.
There are two models of DBMS - relational and schema-free. What relational databases are is described above. Schema-free DBMS based on the principles of the unstructured approach frees the programmer from the problems of the relational model, which include low performance and difficult scaling of data in a horizontal format.
Unstructured databases (NoSQL) create a structure for the course and remove the need to create firmly defined relations between data. Here you can experiment with different ways to access certain types of data.
Relational databases include:
Of these, the most common is the MySQL database, but the rest are also popular and can be encountered.
The principle of operation of such systems is to monitor the strict structure of the data, which is presented in the form of a set of tables. In turn, inside a table, there are cells of the field, which are also managed by the MySQL.
The principle of NoSQL is the MongoDB database. They store all the data as a whole in one database. At the same time, the data can be a single object, but at the same time, any request will not remain unanswered.
Each NoSQL has its own query system, which requires additional study of this system.
Comparison of SQL and NoSQL
If SQL systems are based solely on strict data representation, NoSQL systems provide freedom and are able to work with any type of data.
SQL systems are standardized, whereby queries are generated using the SQL language. At the same time, NoSQL systems are based on a specific technology for each of them, which is a disadvantage.
Scalability. Both databases can provide vertical scaling, that is, increase the amount of system resources for data processing. NoSQL databases, being more a new kind of databases, allows you to apply simple methods of horizontal scaling.
In terms of reliability, SQL has a strong leadership.
SQL-bases have high-quality technical support due to their long history, while NoSQL-systems are very young and it is more difficult to solve any problem.
Data storage and access to their structures within relational systems occurs best in SQL systems.
Reliability of SQL-systems, especially MySQL, is confirmed by time and huge amount of usera. Today, any self-respecting resource uses MySQL system for data storage.