When all the data that are important for the functioning of a certain institution or individual are found in one place, then we are talking about a term known as a database.

According to the definition, a database is a set or collection of data that is organized so that the user is given first quick access to data, and then their quick search.

In addition to the systems for administration, organization, and storage of this data, the database is the so-called database system.

In order for the user to be able to access the database, it is necessary to first fill in an adequate questionnaire, ie to send a request for searching the data either by keyword or initial letters and to reach certain information or group of information in a relatively short time.

Databases are also used to compile reports within a certain organization and in accordance with the rules of its business.

Today, databases have an extremely wide application, because they are characterized by a high degree of reliability and easy operation.

Depending on the type of database, the display of data in it will depend, as well as the way it is used.

Database management systems

A set of services that allow a user to adequately use a particular database is called a Database Management System.

Within these systems, there are a number of services available to the user:

Secondary storage management(storage of data on long-term storage media)

  • Comparative access control(protection systems that allow uninterrupted access of multiple users to a database)
  • Recovery(frequent recuperation of the database in several different places, to prevent the possibility of data loss)
  • Security(mechanisms that protect data from modification by third parties or users who have the authority to access the database but not to change certain data, as well as general access control to a particular database)

Database models

Depending on the model of a certain database, its capabilities will also depend, ie operations that can be applied within a certain database.

The simplest database model is the so-called Tabular Database.

This model consists of a two-dimensional representation of the elements, with all the data in the second column assuming that they are similar values and that indisputably all the elements of the table are interconnected.

The network model of databases is determined according to the CODASYL specification, and the division of data within this type of database is done according to two elements: records and sets(but not sets according to the mathematical definition).

The records are composed of fields, while the sets are in charge of defining the relations between the records according to the system: one to all, ie one owner to all other members.

In this way, the field called “record”, ie the information it contains, has the possibility to be in the role of both owner and members in the meetings.

The search, ie operations in this type of database are carried out according to the principle of searching a certain record, after which the relationships in which it is included are monitored.

A typical mathematical database model, which is designed in accordance with the principles related to set theory and predicate logic in mathematics, is called the Relational Database Model.

There may be a large number of tables within it, but they are not linked by pointers, as is the case with databases that are characterized as networked.

Special “keys” are used to stack rows in all these tables, which can be one or, if necessary, more rows in one table, which is equivalent to columns in another.

In this case, it is not necessary to define these keys in advance, but a certain column can be used as a key, even if it is not originally considered a key.

There is also the term “unique key”, which is intended for universal identification of a certain order in tables, and if such a key is intended to connect to a certain order, then it is called “primary key”.

There are also “natural key”(when the key contains real characteristics, such as personal name or car serial number) and “arbitrary key”(if, for example, there are a large number of people in the database with the same last name, then employees are given an ID number).

A special type of Relative Database Model is the so-called Dimensional Model.

In most cases, such a database is used to store data within a data warehouse.

There are the so-called star and fuzzy schemes of this model, and depending on the needs of the user, the choice of schemes will also depend.

How the database works

In order for the user or a special program to be able to access the database, it is necessary to send a query.

This query, ie the request, is in most cases written in a special programming language, most often in the SQL dialect.

Most SQL queries are built into the software, to make the operation of databases easier and faster.

Then, the database, in response to the query, returns to the user the entire set of results, ie a list of rows in which there are possible answers, that is, the data requested by the user.

This is just the basic principle of operation, with most databases set up to filter the results in a certain way so that the user can get what he wants as soon as possible.

This means that in some cases it can perform an operation known as Merge, ie merge into one table, for example, adequate data from all tables that make up the database.

It is very important that the database is adequately set up, as well as its queries, because only in this way will it work faster and allow the user to easily achieve the desired results.

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