CC BY
9
SCIENCE TIME
PROCESSING TECHNOLOGY OF DISTRIBUTED DATABASES AND IT'S MODEL CONSTRUCTIONS
Agabayev Gurbangeldi Ashirgeldiyevich, Altybayev Sanjar Abdulhakimovich, Amanov Hally Tahirovich, Rustamov Merdan Ramazanovich, Ashgabat, Turkmenistan
E-mail: guwan4@mail.ru
Abstract. Basic models of databases: hierarchical, network, object, object-oriented, relational. Network data model. The results of the study of distributed data processing technology.
Keywords: The data model, network model, the hierarchical structure of the classification database, the server process, the level of abstraction.
Data Model - an abstract, self-contained, logical definition of objects, operators, and other elements that together make up an abstract machine access to the data with which the user interacts. These objects allow you to simulate the structure of the data, and operators - data behavior.
Currently, there are the following basic models of databases: hierarchical, network, object, object-oriented, relational.
The hierarchical structure is a set of elements with each other according to certain rules of communication. Objects related to hierarchical relationships form a directed graph (inverted tree).
The basic concepts of the hierarchical structure are: the level of the element (node) communication.
Node - a set of data attributes that describes an object.
The diagram of the hierarchical tree nodes represents nodes of the graph. Each node on the lowest level associated with only one node, which is at the higher level.
The hierarchical tree has a single node (the root of the tree), not subordinate to any other, and the top is at the top (first) level. Dependent (subordinate) units are on the second, third and so on levels. The number of trees in the database corresponds to the number of root entries. Each database record exists only one (hierarchical) path from the root recording.
The structure of the hierarchical data model is presented in fig.1 [1, p.206].
segment
J the structural part
/ -' field
hierarchical data model
\ means of
\ __J describing data
\i I (AOD)
' controlling part
means of data
manipulation
(DML)
Fig. 1 Structure of a hierarchical data model
The structure of the hierarchical data model (fig.1) consists of a structural part and a control part. The hierarchical structure of the data model is isolated field is the smallest unit of data that is available and the user segment for which are determined by the type and instance. In addition, a copy of the segment is formed from the data field values given in a certain way and a named set of its constituent types of data fields defined segment type.
The main advantages of the hierarchical data model are the effective use of computer memory; high-speed operations on the data; the usability of the hierarchically ordered information.
The disadvantage of the hierarchical model is its bulkiness for information processing with a fairly complex logic connections.
In the hierarchical data model is based relatively limited number of databases, including the IMS can be called a foreign system, PC / Focus, Team - Up and Data Edge, as well as domestic Eye of the system, and the INES Mieris.
The network data model is an extension of the hierarchical approach, described by rigorous mathematical theory, reflecting structural and holistic aspect of data processing, and consists of a set of instances of a particular record type, and a set of instances of a particular type of links between these records.
The main difference of the network structure of the hierarchical data structure is that every element in the network structure may be associated with any other element.
The advantages of the network data model are efficiency in the use of the computer's memory; high speed to perform basic operations on the data; tremendous
opportunities as compared to the hierarchical model of the education of arbitrary connections.
The disadvantages of the network data model are: high rigidity and complexity of the database schema that is built on its basis; difficulty to understand and perform the information processing based non-professional user.
The best-known network database are: IDMS, db _ VistaIII, NETWORK, CETOP and COMPASS.
The object database model is used primarily to create a higher level of abstraction and work with object data, such as image, music, video, and various text,
Feature modern object database model is shown in tab.1 [2, p.199].
Table 1
Modern object model database
name Function name Function
Versant (development of Versant Technologies) is used for the development of telecommunications Versant (development of Versant Technologies) is used for the development of telecommunications
POET (company POET Software) Support for C ++ interfaces, Java, Visual Basic POET (company POET Software) Support for C ++ interfaces, Java, Visual Basic
Object Store PSE (development of Object Design) modules of Java objects Object Store PSE (development of Object Design) modules of Java objects
A relational database is a data warehouse organized into a two-dimensional tables. The tables reflect the type of object (entity), divided into lines that represent instances of the object and the columns corresponding to the attributes, at the intersection which contains the data values forming the basis of the organization of the relational data model.
For ordering of rows in a relational database table model uses primary key that is an attribute or group of attributes, and arranging for one column of the table, the values of which coincide with the values in the other table, the foreign key is used. The relational data model supports operators handle the relationship, such as the relational algebra and relational calculus. The basic rules of the relational data model reflected in fig.2 [3, p.49].
the rule information
the rule of guaranteed access
r
the rule support for invalid values
/ >
the rule for dynamic catalog
based on the relational model
___y
a rule update, add and delete data
Fig. 2 The basic rules of the relational data model
A relational data model distinguished by type connection and power connection, which is the ratio of the number of copies of the parent entity to the child entity corresponding number.
"Client-server" model technology is based on the principle of cooperation between the two software processes, in which the client process asks for some services, and server - to ensure their implementation, one server process can service multiple client processes.
The basis of the "client-server" technology is incorporated division of the standard interactive features of the application (fig.3) [4, p.196].
The basis of the structure of a typical interactive application that works with a database containing [5,p.179]:
- Handling complaints logic that determines what the user sees on his screen when the application is running;
- Business - logic that defines algorithms for solving application problems and is usually created using a variety of programming languages;
- Data processing logic that is responsible for processing data within the application for access, which uses a query language and SQL data manipulation tools;
- Data management processor with the help of which the storage and management of databases where the database functions must be hidden from the business - the application logic.
Also, for the distribution of these functions using two-level model: Remote control model and data model file server.
-m
SCIENCE TIME
The distribution functions in the model data file server shown in fig.4 [6, p.108].
Fig. 3 Functions of technology "client-server"
Fig. 4 Structure of distribution functions in the file server model
The advantage of the file server model is that it does not require separation of the monopoly on the application two interacting process, and the server, as in the "client-server" technology can simultaneously serve multiple clients who turn to him
-m
SCIENCE TIME
with requests.
Disadvantages of file server model are: high network traffic, the narrow range of data manipulation operations and the lack of adequate data access security features.
In contrast to the file server model, in the model of remote access to the data, the database is stored on a server that is also the core database management system, and the client is handling complaints logic and business logic of the application, as shown in fig.5 [7, p.223].
Fig. 5 Remote access to the data model
Remote data access model eliminates the main drawback model file server because of the clients to the server is not transmitted requests for input and output, and structured queries, the volume of which is much smaller, and in response to requests from the client receives only the data relevant request, rather than blocks of files .
Thus, the model RDA, most suitable for implementation using a distributed database SQL queries.
A database is a collection of logically related data that is designed to meet the information needs of users, and database data management system - a software (SW), by which the users can define, create and maintain a database and to obtain controlled access to it.
The classification database DBMS and degree distributions for data storage technology, depending on the nature of the stored information and data storage method as well as content.
A comparative analysis of the main models of databases rightly highlighted the relational model of databases for further research.
Because of studying the technology "client-server" model was considered a
distributed data processing technology based on the principle of interaction between two software processes, in which the client process asks for some services, and server - to ensure their implementation, one server process can service multiple client processes.
Literature:
1. Krenke D. The theory and practice of construction of databases. - Peter, 2010. -S.206
2. G. Miroshnichenko Relational databases. Practical methods for optimal solutions. -SPb. : BHV-Petersburg, 2011. - p.199
3. The Council BJ, Tsekhanovsky VV, damn VD Database. Theory and praktika.- High School, 2010 - p.49
4. Faith C. TCP / IP. Architecture, protocols and implementation (including IP version 6 and IP Security) - Peter, 2011. p.196
5. MySQL. Library professionals - Kiev: Dialectics, 2012 - S.170-179
6. PHP / MySQL for Beginners - Kudits image, 2010 - S.44-108
7. The theory and practice of construction of databases: D. Krenke. - Peter, 2011. -S.223-250
