5.2 Use of the Select of the records (Key F5)
The mechanism of selection, realized in the UNIDAT program, is one
of its most powerful tools. The basic its difference from similar
functions of other similar programs is an opportunity to be carried out
multilevels unlimited number of enclosed time. It allows to allocate a
narrower subset of data from a wider subset, for example allocated in the
previous selection, step by step, moving from more common data to more
specific, with an opportunity of viewing and analysis of the
information on each intermediate stage and acceptance of the decision about a
type of further selection the unlimited number of time (more correctly -
restriction - while the selection will not reach before one unique
record, then already nothing will be further to select).
Selection, just as and other functions, it is possible to make on data from any
field being available in base of any type without restrictions. At multistep
selection at different steps the selection can be made on different fields.
Combining in the free order of a little bit different selections, it is
possible to locate any information, satisfying to any conditions.
For fulfilment of selection it is necessary at first to put the cursor on a
field, on meaning from which records will be selected, and to press
a key F5. After it in appeared small window it will be offered to the user to
enter a key word, after a set of which and pressing on Enter all records with
presence of this meaning in the current field will be
removed on the screen.
RESULT of fulfilment of this team
will be the table with records of a similar kind, as well as the initial table
with entered data, but containing only that records, which were required
according to an inquiry. This table is automatically located in a working zone
of the screen instead of the table with initial data. Then it with
turning out data it is possible to carry out absolutely all actions, stipulated
by the program, as well as with initial data, switching on and repeated teams
of selections, or to an example, any of the rigid reports, which will be formed
on all rules, but only already of this subset.
At fulfilment of
selection on a field, containing line data the program will ask to specify a
method of identification of the necessary data on a key word by a choice from
the menu " Choice on the beginning of a line - Choice on any place ".
At a choice of item " Choice on the beginning of a line " the key line
should precisely coincide with the BEGINNING of lines of required data. And it
is not certain to enter the whole line wholly, it is enough to enter any number
of the initial letters, on which necessary lines will be searched.
At a choice of item " Choice on any place " the given team will select all
records, if the key word will enter required lines in any place inside a field,
on which selection was made.
The second method is more powerful
than first, but in this mode the team is carried out a little bit slowly.
Therefore, if in it there is no valid necessity, it is recommended to use
selection " On the beginning of a line ".
In the program a special mode for realization of an opportunity of selection
for time of all data, satisfying to any of several conditions is stipulated,
even if it is impossible to pick up one common key word. For this
purpose it is necessary to the user to carry out the following sequence of
teams:
1. Establish the cursor on a field, on data of which
selection will come true.
2. Press a combination of keys Ctrl - F5.
3. In appeared window
enter the first key word for the given field.
4. Repeat items
2-3, specifying as a key word other meanings for the given field.
5. If there is the necessity - to repeat steps 1-4, establishing
the cursor on other fields for the task of simultaneous conditions on different
fields (it is possible on fields with different types of data).
6. For start on execution of a common team of selection
on all set forth above and entered conditions (at fulfilment of the
above-stated items of a condition were only remembered in memory) press a key
F5 (already without Ctrl).
If in a working zone not the table with initial data and table with
data, received after fulfilment of a team of selection is displayed, in the
bottom part of the screen under the table of a database there will be visible an
inscription " SELECTION:... " with the indication of a condition,
on which carried out selection.
For return from the table of selected records back in the initial
table it is necessary to press a key F4 (Return).
ATTENTION! It is necessary to remember, that after fulfilment of a
team of selection in a working zone instead of a file with initial data a
special file of selection is loaded. For continuation of input or updatings
of initial data are necessary for carrying out return in an initial file by a
key F4.