Designing of screen forms for work with data

Earlier the mode of direct data input in the table has been considered. It is obvious, that it has rather limited application. It is caused by that the length of record can appear enough big and will enter the information into it in the tabulared form technically inconveniently, and reasons of more basic character:

• First, the structure of the table should be under construction on the basis of logic of problems of storage of the information which, generally speaking, can is essential differ from logic of its(her) accumulation and input
• Secondly, the important parameter of quality of the automated system is the organization of its(her) system of input/conclusion in the form of, as much as possible approached to traditional forms of representation of the information on not machine carriers. Such forms, as a rule, do the software attractive to the end user, reduce the period of its adaptation to again introduced system and allow to concentrate quickly on the decision of the basic professional problems
• Thirdly, in the complex and developed automated information system division of access to various groups of fields and records for categories of users depending on functions carried out by them should be provided. Also in the certain situations it is required to present the same information or in various kinds and cuts, or in various combinations to other information.

For the decision both these, and many other things of problems of the organization of the interface ввода/a conclusion of data in Access serves the mechanism of electronic forms. We shall choose вкладку Forms of the main window of a database and we shall press the button To create. An appearing dialogue window allows to choose as the table or inquiry, for work with which data the form, and a mode of its creation is made. Depending on qualification of the user and, naturally, complexity of the developed form can or take advantage of the built in program superstructures-masters, or at once to begin its creation with zero in a mode of the Designer. Rather fruitful also there is a combined approach: first the corresponding master is used, and then the received form in addition is finished in " a manual mode ". We shall illustrate told on an example. We shall create the form for work with the table of the Paper, having taken advantage of a superstructure the Autoform: in a column. As a result we shall receive a window of a following kind.

By default it was offered to form to appropriate the same name, as well as at the table on the basis of which it has been created, that is Papers. Apparently from fig., at creation of signatures of fields the program superstructure used them соответствущие the attributes set at designing of the table. The last not always happens convenient from the point of view of the interface of the user. For elimination of these and similar lacks we should return to a mode of change of a breadboard model of the form (the button the Designer or the pictogram the Kind on the panel of tools

On fig. the same form in a mode the Designer is shown. The technology of process of designing of forms in Access environment is reduced to addition of operating elements and change of their properties. In this connection at transition in a mode of the Designer on the screen by default there are two additional windows:

• Window the Panel of elements which is intended for a choice of the next operating element added to the projected form. In the designer of forms Access such elements of management as an inscription, a field, the button, a tag, the switch, the list, a set вкладок, etc. Besides it(this) to the form it is possible to connect special elements of management OLE are built in, that considerably expands opportunities of development of the interface of management with data.
• Window of Properties of a current element of the management, intended for change of its attributes and adjustments, for example, colors, a font, the size and т. Item

In a mode the Designer the structure of the form is obviously visible. It) consists of three parts: Heading of the form, Area of data and the Note of the form. As it is easy to guess, such structure first of all is focused on opportunities of representation таблично the organized data. We shall notice, that both the form, and its sections also are considered as the elements of management possessing some adjusted sets of properties.
By way of illustration opportunities of the designer on change of the interface of input/conclusion we shall lead following manipulations above the form of the Paper:

• Let's remove background figure: we shall clear property Figure when chosen by an element the form is current
• Let's change color of a background: we shall choose element ОбластьДанных and we shall change at it attribute Color of a background
• Let's change appearance water: we shall allocate group of fields (fields get out by means of the mouse at pressed key Shift) and in a window of properties we shall change value of attribute Registration on Drowned
• Let's edit signatures of fields and we shall change their arrangement from each other a little: for this purpose it is enough to take advantage of opportunities of visual editing of elements
• Let's add a dividing line after field НаимБум (the name of a paper): for this purpose it is necessary to take advantage of an element the Line

Let's add the button of end of work with the form: in the majority of situations and similar operations it is easier and more convenient to do this in a mode of the master (the corresponding button is pressed panels Elements of management). In this case from the user it is required to enter only a minimum quantity of parameters for an added program component. The added button we shall place in area of the Note of the form. As a result edited form of the Paper of signs a following kind

The example of the organization of data input/conclusion in the table of the Paper by means of the same form carries somewhat вырожденный character: in it structure water in the form of unequivocally corresponds to their structure in the table. However, as a rule, at creation of real appendices it is necessary to solve a problem(task) of management of the Data who are being system of interconnected tables, of the uniform form. As an example we shall consider a problem of construction of the form in which for each given paper the information under applications for its purchase and sale simultaneously is deduced.

Its appearance is resulted on fig. the Top part of the form corresponds to a current line of the table of the Paper and varies at transition from record to record which can be made by means of the arrows located in the bottom part of a window. Lines of tables of the Application for sale and Applications for purchase in which the information concerning a current paper is deduced(removed) only simultaneously should vary.

Let's consider in more detail those means Access by means of which such result can be received. It is the so-called complex/or compound form (Applications on papers). Process of its creation consists of two basic stages:

• Creation of the basic form. For this purpose the actions similar to what were carried out at creation of the form of the Paper are carried out
• Creation of the subordinated forms. For this purpose in the created main form the element of management the Subordinated form is added

At creation of the subordinated form in Access exists two basic opportunities:

• To create the new form on the basis of some table or inquiry
• To take advantage of already existing form, having made its subordinate

In this case two new subordinated forms are created. And they are created on the basis of special inquiries. Such decision allows to allocate separately from the general table of the Application of record with applications for sale and for purchase. In particular, inquiry ЗаявПрод returning sample of applications for sale of securities, has the structure shown on fig. As advantages of such approach to the organization of a source of data for the subordinated form it is necessary to note the following moments:

• In auxiliary inquiry simply enough to process a condition identifying type of the application (if the volume of the application is less than zero it is the application for sale). Moreover, for the end user as volume of the application instead of negative sizes positive values looking more naturally-1 * [0бъем3аявки] are deduced
• Data are deduced sorted on increase of the offered prices, that undoubtedly simplifies process of work with them in the screen form

The inquiry returning to record with applications for purchase, is created similarly in view of updating a condition selection.

The most essential moment during introduction of the subordinated form in main is the correct task of a condition of communication(connection) between them. In many cases with it(this) program superstructures of masters correctly consult. Thus they use the information from the scheme(plan) of data and descriptions of structure of tables. In to, time, it is not necessary to forget and about opportunities of change of conditions of communication(connection) between the leader and subordinated by forms in a manual mode. For this purpose it is necessary to change attributes in an element of management the Subordinated form, being in a mode the Designer.

The author: Y.N.Antonov Is added: 20.06.2008