Материал: Крючков Фундаменталс оф Нуцлеар Материалс Пхысицал Протецтион 2011

There must be an understanding that the examples given include the simplest queries to illustrate the use of SQL for manipulation of data. The language capabilities are remarkably greater and make it possible to generate complex queries to cover practically all user demands. Literature is abundant to give anyone a profound knowledge of SQL.

Many DBMSs include objects which are precompiled and optimized SQL queries. An example of these is stored MS SQL Server procedures. Such queries are highly fast to execute. A user-data interaction can be also organized such that to provide the user with access to only stored procedures and not to the data these operate. This sets up an additional data access security barrier.

Use of DBMS in computerized NM A&C systems

As of the time this chapter was being compiled, developers had a limited choice of two SQL servers certified to access security class 3. These are Microsoft’s SQL Server, version 6.5, and two Oracle DBMS versions. Being highly expensive, Oracle products have a confined application. MS SQL Server is available at a more affordable price and offers a power adequate for corporate applications at different levels. The most recent Oracle DBMS applications include the Federal Information System and a number of major operators in the industry. Most other products operate MS SQL Server 6.5 [13]. Likewise operating systems, new software products are subject to certification. Plans exist to have MS SQL Server [14] and Oracle 10 certified to access security class 3. Apart from DBMSs designed to operate in Windows OS environments, another DBMS, PostgreSQL, has been certified along with a secure Linux distributive.

7.3.3. Development tools

Development tools form the third component of base software for computerized NM A&C systems. These have two important roles in design and operation of systems. First, developers use them to create a graphic user interface (GUI). Nowadays, one cannot imagine a marketable software product without a developed and convenient interface. The second role of applied software is to ensure the integrity and security of information by program features. Depending on the type of the DBMS based on which an A&C system is built, this role may turn out to be central. Thus, MS Access, a popular DBMS, has most data integrity control functions vested in forms, that is, in applied software. In contrast, MS SQL Server realizes these

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functions on the server. No binding certification requirements to development tools exist.

There are some requirements imposed on such tools by the industry standard. These require that tools should provide the developer with:

∙convenience of program development;

∙visual programming capabilities;

∙good debugging features;

∙a developed error handler;

∙support of multiwindow environments;

∙convenience of communication with databases.

Some of the requirements are general, though two well-defined requirements exist that limit the number of tools that satisfy to the standard. These require that visual programming and database communications should be in place.

Visual programming is to be understood as a capability to generate a user interface with the aid of readymade graphic control objects. The programmer simply gets them on the work form and defines further the functionality thereof. Systems of the kind make it much easier for anyone to form an interface and give the ability to create professionally looking program in the Windows environment even to developers with limited programming skills.

There are different ways to organize communications with databases in a software environment, still professional systems exist that incorporate dedicated objects and features enabling the user to get access to data in various formats.

Current software development systems offering such capabilities are rather many. The most sought-after systems are Microsoft’s Visual Basic and Visual С++, and Borland’s Delphi and C++ Builder.

According to a survey, in 2001 about one third of corporate developers in Russian nuclear industry employed Visual Basic and some 15% used Delphi. The existing demand for VB in domestic community of computerized NM A&C system developers is attributed chiefly to the experience of LANL experts who created CoreMAS, a product which, though not adopted to date in the industry, has been used as the model to build many Russian-developed systems. VB is also rather a simple and convenient software system various versions whereof offer ample data access capabilities.

There is one more point to application development systems to mention. While not being formally adopted in the industry standard, this has long established itself as a standard for all professional application development

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systems by expecting each development tool to support object-oriented programming (OOP). We shall discuss the principles thereof in brief [15].

Object-oriented programming

The difference of OOP from traditional procedure-oriented programming consists chiefly in the following. In object-oriented programming, program is a set of specific objects with specific properties that act and respond to user actions. Program, in fact, turns into a process of user interaction with the program objects. When responding to any user manipulations, the program, or more precisely, the objects therein will operate in this or that way. This approach offers more flexible programming and allows one to escape a great deal of complexities involved in debugging, which comes down to testing methods and properties of the object rather than of the entire bulky program.

This leads to a question of what an object in OOP is. To answer it, let us take a brief look at the sequence of program units. An identifier defines any one value, say, color. Further, all current programming languages use the notion of record as a set of identifiers. One can create a record that contains a rectangle screen location (four numbers), a color (one number), a caption (character string) and a position - if the button is pressed or not pressed (Boolean variable). Such record gives a complete identification of the menu button in the form. Object-oriented programming goes even further. The object incorporates the procedure that realizes some action to be performed by pressing the button. This is called method and this procedure is accessible only from the object. The object so includes not only data but also a program code. Where many buttons are created, the method of each of these will relate to the parameters, that is, the properties of this very button.

Let us formulate the basic OOP-related concepts.

Object – a program unit that contains a complete descript ion of the entity programmed, including data and the program code which enables some object-inherent actions to be realized.

Object properties – define the essence of the object, e.g. appearanc e for visual objects or data source for database-related objects.

Event – an object-related action or situation. For a gra phic object, e.g., button pressing is the event that relates to the mouse click on the button. An event may result not from a user action but from an action of the program or the operating system (when time comes or the iteration process converges).

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Method – a program module (procedure, subprogram, function ), which processes object-related events.

Class – an object template. An object with filled in prop erty values is an instance of the class.

The following concepts characterize OOP:

encapsulation – integration of data and the program code while concealing their realization methods from the user. The user access to the object is provided only via respective methods and events;

inheritance – one can create classes based on the existing clas ses with methods and properties being inherited;

polymorphism – derived objects know exactly to what method an e vent should be passed to be handled. Thus, a child may have a method which has the same name as the parent’s one but is different in properties. For example, the cool looking button and 3D–button obje cts have ”pressing” one name as their event handling method but use different pressing display graphics. Then, if the 3D–button is the child, its method will be called.

Current program development environments that take the objectoriented approach are rather many. Most of these systems use C++ as the programming language. Object Pascal is utilized by Delphi. Microsoft Visual Studio.NET includes Visual Basic 7, which has eventually been given all the properties an object-oriented programming language is expected to possess.

The choice of the software development environment shall be primarily defined by corporate or industry standards. An enterprise normally has a staff of qualified programmers who have a good command of customary development tools. A shift to new development tools is dictated by the requirement to adopt novel technologies calling for special programming patterns; employ a DBMS including development tools and change over to a new operating system.

Certification of base software on an open code basis has led to the possibility of using program development tools compatible to this environment. Java-based J2EE (Java2 Platform Enterprise Edition) can be used as the platform for such tools. We shall further dwell on the concept of program development platform and the advantages it offers to the database application developer.

Program development platforms

There are now two rival program development platforms: Sun Microsystems’ J2EE (Java2 Platform Enterprise Edition) [16] and

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Microsoft’s .NET [17] (read as “dot net”). Both pla tforms enable creation of user applications of different architectures. To start with, these are classic client/server applications. Most current computerized NM A&C systems use exactly this architecture. Another capability provided is creation of Web–applications. This requires only a browser program, which is part of many operating systems, to install into the workstation. Web– server is where the application operates, communication with data is organized and Web-pages to be supplied to the user are formed. Finally, both platforms offer a new application development method which creates and uses Web-services. Web–services hinge on their ability to transmit data from the supplier to the consumer via a standard HTTP protocol. XML is used as the data format. The available standard data formatting and transmission facilities help create applications that do not rely on hardware platforms. The user application makes a query which is sent to a Webservice via HTTP. The query result is transformed into an XML format and delivered to the user. XML is a dedicated data markup language used to communicate data and is readily transformed into browser-viewable formats. Web–services can be referred to both from the Web–application and from a standard workstation-based application.

The two platforms are of nearly the same functionality. They differ mostly in cross-platform application transportability and capabilities to support various programming languages. J2TT is now the only program development environment with multi-platform support features. Microsoft customarily makes use of its own proprietary operating systems.

On the other hand, J2EE uses one development language, Java, while Visual Studio.NET. includes four: Visual Basic, C++, С# and Java. For an enterprise using Microsoft products for its base software, .NET offers a minimum-cost option of changing over to new technologies. Those using Visual Basic to design database applications will find it easy to switch to VB.NET-based programming of Web–services in their c ustomary program development environments.

Changing over to open-code operating systems will yet require use of other development tools and so then J2EE becomes a natural choice.

Support of application/data communications

To be able to satisfy to a major industry standard requirement in the context of future computerized NM A&C systems, development tools should possess dedicated database access features. Microsoft has developed a spectrum of object class collections that model the database structure and

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