The basic development cycles of a database in MS Access environment

Process of development of the concrete program appendix in Access environment first of all is defined by specificity of an automated subject domain. However for the majority of them it is possible to allocate a number of typical stages. It:

• Development and the description of structures of tables of data
• Development of the scheme of data and the task of system of interrelations between tables
• System engineering of inquiries to tables of a database and (if necessary their integration into the scheme of data
• Development of screen forms of data input/conclusion
• System engineering of reports according to
• Development of program expansions for a database, solving specific problems in processing an information containing in it, by means of macroowls and modules
• System engineering of protection of data, the rights and restrictions on access

Between the listed stages exists big quantities of the feedback meaning return to earlier steps, proceeding from again opened circumstances which it was impossible to consider in advance silt to expect.

 Development of economic appendix MS Access

Reasonableness of user interface Access does its especially attractive as means of the decision of problems of the organization and data processing for experts in the field of economy and the finance which is simultaneously not having qualifications or experience in professional programming. We shall make a reservation, that here it is a question of the appendices created by such expert for own using. At the same time, as soon as there is a necessity for development of means for other users, without programming as rules to manage it is not possible.

We shall stop on an example by means of which, it is possible to illustrate evidently the majority of the most important functionalities of this software product.

Let's assume, that before us there is a problem of automation of managerial process by the tenders by a set of financial actives on some limited sector of the market. For its decision well approaches MS Access.

Let in the market (in some trading system) circulates the certain set of securities (actions), each of which is characterized by the name, a nominal price, total volume of a package (that is how many all units of the given paper has been emitted), date of issue. Simultaneously in the market its subjects who can sell and buy papers operate. Each agent is characterized at least by the name and size of means which it possesses. Thus, four data files are naturally defined on:

• To papers
• To agents (market)
• Accessories of papers to agents (on portfolios)
• To applications of agents for purchase or sale of those or other papers

Let's describe structures of streams of the information which appear in an automated subject domain, at more logically strict level.
The file of data on existing actives (we shall appropriate to it a name of the Paper) will contain columns:

• Code of a paper
• The name of a paper
• Nominal price
• Total volume of a package
• Date of issue
• Type of a paper (for example, the action or the bond)
• Accordingly, the table Agents will consist of columns:
• Code of the agent
• The name of the agent
• Volume of money resources which the agent possesses
• The comment on the agent

Let's notice, that weeding the Code of a paper and the Code of the agent are the keys providing unique identification of records in corresponding tables.

For storage of the information about the maintenance of portfolios of securities which agents own, we shall create the table Portfolios with structure:

• Code of a paper
• Code of the agent
• Quantity of papers of the given name in a portfolio which the given agent possesses

In the table Portfolios we collide with a compound key which is formed with a combination water the Code of a paper and the Code of the agent. At last, the information those intentions or other agents to sell those or other papers we shall place in the table of the Application:

• Code of the application
• Code of a paper
• Code of the agent
• Volume of the application (in terms of the measurement, corresponding papers of the given name)
• The price of the application

Let's note, that the economic maintenance put in size, containing in a field Volume of the application, can have various interpretations. For example, it is possible to consider, that if this value is positive, it is the application for purchase and if it is negative - on sale. It is obvious, that alternative decisions on the organization of the given table are possible also. For example, it would be possible to create two separate weeding: Volume of the application for purchase and Volume of the application for sale. In addition it would be desirable to pay attention to those reasons according to which as a key the separate field the Code of the application is used. It allows to store simultaneously in the table different offers on the same paper, acting from the same agents.

The author: Y.N.Antonov Is added: 18.06.2008