Dağıtık veritabanı mantığına dayalı sigorta otomasyonu

Abstract

Proje konusu olarak, sigortacılık sektöründe, birden fazla coğrafi yerel yapı üzerinde hizmet veren sigorta şirketi ve acentaların poliçe ve reasürans işlevlerini gerçekleştiren bir uygulama geliştirilmiştir. Uygulama, acentaların işlemlerini merkeze bağlanmak zorunda olmadan gerçekleştirmeleri ve gerektiğinde birbirleri ile iletişim kurmaları baz alınarak dağıtık veritabanı yönetim sistemine göre tasarlanmıştır ve veritabanı uygulamaları, Oracle veritabanı yönetim sistemi üzerinde gerçekleşmektedir. Acentalarda Unix makinalar bulunmaktadır. Bir bilgisayar ağına bağlı coğrafi bir alana dağılmış olan bu makinalar, birbirine X.25 uzak iletişim ağı ile bağlıdır. Her makinanın kendi yerel veritabanı vardır ve gerektiği zaman istemci/sunucu mimarisi kullanılarak bu veritabanları arasında bilgi akışı gerçekleşmektedir. Tez, dört ana bölümden oluşmaktadır; Birinci bölümde, iletişim ağlan, topolojiler, TCP/IP, OSI modeli ve katmanları, Internet protokolü, bağlantı şekilleri incelenmiştir. İkinci bölümde, dağıtık veritabanı ve yönetim sistemi ile ilgili temel kavramlar, temel özellikler, hareket yönetimi, güvenirlilik, şeffaflık, problemler, avantajlar ve dezavantajlar anlatılmıştır. Üçüncü bölümde, Oracle veritabanı yönetim sistemi hakkında bilgi verilmiş ve dağıtık mimarisi incelenmiştir. Dördüncü bölümde ise proje konusu, iş akışı, veritabanı uygulamaları ve çeşitli programlar yer almaktadır.

Database management has evolved from a specialized computer application to a central component of a modern computing environment. A database management system (DBMS) consists of a collection of irterrelated data and a set of programs to access that data. The primary goal of a DBMS is to provide an environment that is both convenient and efficient to use in retrieving and storing database information. The DBMS acts as an interface between the stored database and the users of the database. Database systems are designed to manage large bodies of information. The management of data involves both the definition of structures for the storage of information and the provision of mechanisms for the manipulation of information. In addition, the database system must provide for the safety of the information stored, despite system crashes or attempts at unauthorized access. If data is to be shared amoung several users, the system must avoid possible anomalous results. The importance of information in most organizations, and hence the value of the database, has led to the development of a large body of concepts and techniques for the efficient management of data. The most widely used types of DBMSs are the hierarchic, network and the relational. From a historical perspective, the relational data model is relatively new. The first database systems were based on either the network model or the hierarchical model. Those two order models are tied more closely to the underlying implementation of the database than is the relational model. In the years following the introduction of the relational model, a substantial theory has developed for relational databases. This theory assists in the design of relational databases and in the efficient processing of user requests for information from the database. The relational model has established itself as the primary data model for commercial data processing applications. Relational systems offer benefits such as; - easy access to all data - flexibility in data modelling - reduced data storage and redundancy - independence of physical storage and logical data design - a high-level data manipulation language (SQL) Xll After this development of database systems, computer networks have been developed, allowing the connection of different computers and the exchange of data and other resources between them. In recent years the availability of databases and computer networks has given rise to a new field: distributed databases. The data which constitute the database are stored at the different sites of the computer network, and the application programs which are run by the computer access data of different sites. In this study, an application which is built on the idea of distributed database system on the insurance sector is developed. Insurance is an agreement made to protect the loss of a person or a company by being paid a specific amount of money. Insurance companies are the companies whose establishment is specified with definite laws and regulations. They assure other companies and people that require to be insured. The insured people are the ones whose belongings or lives are assured by the insurance companies. The relation between the insured people and the insurance company can be established both when one of them attempts to do this or through the insurance brokers. These brokers are called agent. The types of insurance are called branch. Fire, transportation, car are examples for the branches. The risks which are insured in these branches are each called assurance. Schedules are the combined forms of the assurance. All this information is piled on a piece of paper which is called the insurance policy. If we show it with a simple figure, it is as follows; assurance J schedule branch assurance J schedule ^\ assurance ~| schedule Figure 1. Relationship between branch, assurance, schedule. The other important subject is the term of reassurance. Reassurance is the sharing of the risk amoung different companies by being paid a specific amount of money. In this way, the insurance company provides both the insured ones and its own security. Reassurance is the international agreement designed between the insurance companies and the reassurers and with its simplest definition, it is the insurance of the insurance company. The service in which these terms are employed is the technical service. Apart from this, in the department of damages, the damages are examined and the Xlll necessary operations are started determining the probable damages. In the accounting department, the invoices of these damages are prepared and other necessary applications are processed. All the structure is built upon a distributed database using the advantages of distributed processing. Distributed Processing uses more than one processor to divide the processing for a set of related jobs. Distributed processing occurs when an application on one CPU accesses a database on another CPU. Figure 1 refers to an architecture in which a database resides on a different machine to the user process accessing it. It reduces the processing load on a single processor by allowing different processors to concentrate on a subset of related tasks, thus improving the performance and capabities of the system as a whole. A database can easily take advantage of distributed processing by using its client-server architecture. In this architecture, the database system is divided into two parts; a front-end or a client portion and a back-end or a server portion. Remote computer Local computer Figure 2. Distributed processing. The client portion is the front-end database application and interacts with a user through the keyboard, display, and pointing device such as a mouse. The client portion has no data access responibilities; it concentrates on requesting, processing and presenting data managed by the server portion. The client workstation can be optimized for its job. For example, it might not need large disk capacity or it might benefit from graphic capabilities. The server portion runs RDBMS software and handles the functions required for concurrent, shared data access. The server portion receives and process SQL and PL/SQL statements originating from client applications. The computer that manages the server portion can be optimized for its duties. For example, it can have large disk capacity and fast processors. xiv A distributed database system consists of a collection of sites, connected together via some kind of communications network, in which i) Each site is a database system site in its own right, but ii) The sites have agreed to work together (if necessary), so that a user at any site can access data anywhere in the network exactly as if the data were all stored at the user's own site. Each site has its own local real databases, its own local users, its own local DBMS and transaction management software and its own local data communications manager. The distributed database system can thus be regarded as a kind of partnership amoung the individual local DBMSs at the individual local sites. The primary benefit of a distributed database is that the data of physically separete databases can be logically combined and potentially made accessible to all users on a network. All of the application is developed by Oracle RDBMS. The Oracle RDBMS is the central Oracle product. Oracle Corporation was the first company to offer a true relational DBMS commercially, and has continually led innovations in the field of RDBMSs. The Oracle RDBMS includes the database manager and several tools intended to assist users and DBAs in the maintenance, monitoring and use of data. It is a high- performance, fault-tolerant database management system, especially designed for online transaction processing and large database applications. At the heart of the Oracle RDBMS is the SQL data language that is used for most database activities. SQL is simple enough to allow beginning users to access data easily and quickly, yet it is powerful enough to offer programmers all the capability and flexibility they require. SQL was developed and defined by IBM Research, and has been refined by the American National Standards Institute (ANSI) as the standard language for relational database management systems. The SQL implemented by Oracle Corporation is a superset of the standard SQL data language. An Oracle database can be used in a configuration as a distributed database. Oracle configured with SQL*net supports distributed queries. When data is required from remote databases, a local database server communicates with the remote database using the network, network communications software, and Oracle's SQL*net. SQL*net is the interface used to connect clients and servers that operate on different computers of a network. SQL*net also cannects database servers across networks to facilitate distributed transactions. SQL*net and Oracle's distributed database system run on most networks, the particular type of network protocol or topology does not matter. xv For the distributed organization on the project, the client-server architecture and the database connection properties of Oracle were used. As the subject of my project, I developed an application realizing policy and reassurance activies of the agenties and insurance company that serve in the sector of insurance on more than one geographical local structure. The application has been planned according to distributed database management system. As far as this application is concerned, agent can perform their operations without necessarily having to be connected the center and applications of the database process on the Oracle database management system. There are Unix machines in the agenties. This machines, which are distributed to a geographical area connected to a network, are connected with each other by X.25. Every machine has its own local database and data flow amoung this database could be realized using the client/server architecture whenever necessary. Database 1 6 - S Figure 3. A distributed database on a geographically dispersed network. xvi My thesis consists of four main sections. In the first section, network, topologies, TCP/IP, OSI model and layers, the Internet protocol, connection types are scrutinized. In the second section, basic terms related with distributed database and management system, basic properties, transaction management, reliability, transparency, problems, advantages and disadvantages are revealed. In the third section, information about the admistration system of Oracle database and its distributed architecture are mentioned. Finally, in the last section, subject of the project, job flow, database applications and various programs are examined.