Data base
OpenOffice.org Base: database management system of datos.Una database or database is a dataset within the same context and stored systematically for later use. In this sense, a library can be considered a database consisting mainly of documents and printed on paper and indexed for reference. At present, due to technological development in fields such as computing and electronics
most databases are in digital format , which offers a wide range of solutions to the problem of storing data.
There are programs called database management systems for data, abbreviated DBMS, to store and subsequently access data quickly and structured. The properties of these DBMS and its use and administration, are studied within the field of computing.
The most common applications are for the management of companies and public institutions. They are also widely used in scientific environments in order to store the experimental data.
Database Models
In addition to classification by function of the databases, they can also be classified according to their data management model.
A data model is basically a "description" of something known as a container of data (something where information is stored), and methods to store and retrieve information from these containers. Data models are not physical things: they are abstractions that allow the implementation of an efficient database, generally refers to algorithms and mathematical concepts.
Some models are often used in databases:
Hierarchical databases
Main article: Hierarchical Database
These are databases which, as its name suggests, store their information in a hierarchical structure. In this model data is organized in a manner similar to a tree (seen upside down), where a parent node of information can have several children. The node has no parent is called root, and nodes without children are known as leaves.
The hierarchical databases are especially useful for applications that handle a large volume of information and data sharing allows very stable structures and high performance.
A major limitation of this model is its inability to efficiently represent data redundancy.
Network Database
Main article: Network Database
This is a slightly different from the hierarchical model, its main difference is the modification of the concept of Node allowing a single node has several parents (can not allowed in the hierarchical model).
It was a great improvement over the hierarchical model, as it offered an efficient solution to the problem of data redundancy, but even so, the difficulty in managing information in a database network has meant that is a model used in mostly by programmers rather than end users.
Transactional database
Are databases whose sole purpose is to send and receive data at high speeds, these bases are very rare and are usually directed to environment quality analysis, and industrial production data, it is important to understand that its sole purpose is to collect and retrieve data as fast as possible, so the redundancy and duplication of information is not a problem as with other databases, usually to make the most they could be allowed some sort of database connectivity relational.
Relational databases
Main article: Relational model
Main article: Relational database
This is the model currently used to model real problems and manage data dynamically. After being nominated its foundation in 1970 by Edgar F. Codd, IBM laboratory in San Jose (California), was soon established as a new paradigm in the model database. His basic idea is the use of "relationships". These relationships could logically be considered as sets of data called "tuples". Although this is the theory of relational databases created by Codd, most of the time is conceptualized in a more easy to imagine. This is thinking in every relationship as if it were a table that consists of records (rows in a table), which represent tuples, and fields (the columns of a table).
In this model, where and how they store data are not relevant (unlike other models such as the hierarchical and network). This has the considerable advantage of being easier to understand and use for an occasional user of the database. Information can be retrieved or stored through "consultations" that offer a wide flexibility and power to manage information.
The most common language to build queries to relational databases is SQL, or Structured Query Language Structured Query Language, a standard implemented by the main engine management systems or relational databases.
During its design, a relational database through a process that is known as normalizing a database.
During the '80s, the emergence of dBASE produced a revolution in programming languages and data management systems. Although dBase never forget that language did not use SQL as the basis for its management.
Multidimensional Databases
Main article: multidimensional database
Databases are designed to develop niche applications, such as creation of OLAP cubes. Basically do not differ too much from the relational database (a table in a relational database could be also in a multidimensional database), the difference is more conceptual level, in the multidimensional database fields or attributes a table can be of two types, or dimensions of the table represent or represent metrics that want to study.
Databases Object-oriented
Main article: Database Object Oriented
This model, quite recent, and typical of the object-oriented computer models, is stored in the database the whole objects (state and behavior).
A database is an object-oriented database that incorporates all the important concepts of the paradigm of objects:
Encapsulation - Property that can hide the information to other objects, thus preventing improper access or conflict.
Inheritance - Property through which objects inherit behavior within a class hierarchy.
Polymorphism - Property of a transaction which can be applied to different types of objects.
In databases, object-oriented, users can define operations on the data as part of the definition of the database. An operation (call function) is specified in two parts. The interface (or signature) of a transaction includes the name of the operation and data types of its arguments (or parameters). The implementation (or method) of the operation is specified separately and can be modified without affecting the interface. The application programs users can operate on data referring to these operations through their names and arguments, in whatever way they are implemented. This could be called independence between programs and operations.
SQL: 2003 is the extended SQL92 standard, supports object-oriented concepts and maintaining compatibility with SQL92.
Documentary Databases
They enable full text indexing, and generally perform more powerful searches. Thesaurus is an index system optimized for these databases.
Deductive databases
A system of deductive database is a database system but with the difference that can make inferences through inferences. It is based mainly on rules and facts that are stored in the database. Deductive databases are also called logical database, following which is based on mathematical logic.
Managing distributed databases
The database is stored on multiple networked computers. Arise because the physical existence of agencies. This gives them the ability to link the databases of each locality and thus gain access to various universities, branches of shops, etcetera.
Publicado por: Orlayde Alvarez
Entradas
