Acorn Risc Technologies StrongARM CD-ROM/Acorn Risc Technologies StrongARM CD-ROM.iso/software/apps/powerbase/Docs/Customise

Text File | 1995-08-21 | 15.9 KB | 324 lines

Ch 14 − Customising Powerbase

This chapter describes all the things you can do to influence the way
Powerbase looks and functions.

14.1  Overall control of the database

A Powerbase database is normally controlled in four ways:−

•       mouse-clicks on the keypad

•       keystrokes which mimic the actions of the keypad

•       choices from the main menu

•       choices from the icon-bar menu

Each of these can be disabled by deselecting one of the option switches on
the Password window (see 11.2).  The main reason why you might want to do
this is to provide limited facilities to someone else who is using your
database.  It doesn’t, on the face of it, make a lot of sense to disable
both the keypad and the keystroke-equivalents as no browsing or editing
would then be possible.  You can, however, place some or all of the keypad
buttons on the record screen itself (see 4.2.9) thus allowing you to choose
what functions you want to allow access to.  You might, for example, wish to
provide only the “Next record”, “Previous record” and “Search” buttons.
Define these as Button fields at the time the record is being designed then
disable the keypad and keystroke equivalents.

Other switches in the Password window enable you to stop the user exporting
data as CSV files or subsets or printing reports.

14.2  Defining the function keys

Any button on the keypad may have its action duplicated by one of the keys
F1-F11, with or without the use of Shift, Ctrl or both.

Point at the button to which you wish to assign a key and click MENU to
display the keypad menu. Assign leads to a window which shows the present
key-assignment, if any. Use the “bump” icons to select the required function
key and, if desired, select one or both of the switches for Shift and Ctrl.
Click on the Assign button and you will now find that the assigned key
exactly mimics the keypad button − even to the extent of actually “pressing”
the button when you type the key.

One important constraint should be noted. Whatever key you assign to the
Search button, Powerbase will automatically assign the shifted version of
this key to the “search all subfiles” function (see 2.3.1). For this reason
you should assign an unshifted key to Search and avoid assigning the shifted
version to any other keypad button.

You may save your key definitions by choosing Save choices from the keypad
menu and you will find them operative next time you use Powerbase. Please
note that your definitions work with all the databases you use; there is no
facility for saving separate assignments for each database. The default
keystrokes (together with some which duplicate non-keypad actions) are
listed in Appendix B.  If they have been redefined you may restore the
defaults by choosing Defaults from the keypad menu. If you wish to “lose”
the redefined keystrokes permanently you should restore the defaults as
described then Save choices.

List keys on the keypad menu displays all the key definitions (including
those for non-keypad functions) in a window from which the information may
be saved as a text file.

14.3  Print options

The Print options window, accessible from the Print submenu or by typing
Shift Print, was described in some detail in 3.5 but a few features still
require comment.  You may set up this window to suit the requirements for a
particular database and then save the set-up as part of the database by
clicking on Save choices with the in database radio button selected.

A Save box appears which, by default, saves the options file in the PrintRes
directory under the name PrtOptions. A file of that name, in that directory,
is read when the database is subsequently re-opened and will set up the
print options as you left them. You can, of course, give the file a
different name and even save it in a different place if you wish.  Print
option files are recognisable by their icon, which bears a large “P”.  Some
users like to have several of them in their database’s PrintRes directory to
do different jobs. It is always possible to load the one you want by opening
the PrintRes directory (Show resources from Print submenu or, alternatively,
Ctrl R) and double-clicking on  the required file or dragging it onto the
record window.

Should you wish to “throw out” your special keys set-up during a working
session with the database you can restore the default settings by clicking
Load default. If you like your own setup better than the default and wish to
use it for all your databases then select the as default radio button before
clicking Save choices.  The file PrtOptions will then be saved inside
Powerbase itself. Note also that, provided the Print options window has not
been closed, the Cancel button will restore it to the state it was in when
you opened it.

14.4  CSV options

It was explained in 8.2 how to access the CSV options window and what the
pop-up menus and option switches are for.  The buttons Save choices, as
default, in database, Load default and Cancel work in a similar way to that
described above for the Print options window − with one notable difference.
No Save box appears when you Save choices in database; the file is saved as
a plain text file called CSVoptions. This more limited behaviour has been
chosen because, although you might want several Print options files for
different jobs, it is unlikely that you will have a use for several CSV
options files.

14.5  Preferences

Several previous references have been made to the Preferences window which
is opened from the icon-bar menu. A full description of the choices offered
in this window follows.

14.5.1 Separators in date and time fields

By default dates have the format dd-mm-yy or dd-mm-yyyy, i.e. the separator
is a hyphen. You might wish to use a colon, full-stop, slash or other
character. You may type any non-numeric character when entering dates and
Powerbase will re-format the field to use the specified character.  Only
fields actually defined to be of type Date behave in this way.

Fields defined to be of type Time have the form hh:mm:ss, i.e a colon is
used as the separator. As in the case of dates, you may type any non-numeral
you like during data entry and Powerbase will reformat the time as above.

To change either of these separators type the required character into the
writable icon in place of the default.

14.5.2 Wild-cards

The use of wild-card characters is described in 2.7.5 and 3.3.4.  By default
“#” represents a single character and “$” a group of characters which need
not be matched.  You may change either or both wild-card characters if you
wish in the same way as described above for date and time separators.

14.5.3 Option switches

Launch new copy, when ON, causes another copy of Powerbase to be loaded when
you double-click on a database, instead of closing the current database.
This can be useful if you want to access several databases at once, as one
copy Powerbase only supports the use of a single database. If there is a
dormant copy of Powerbase on the icon-bar (i.e. one with “No data” under its
icon) then double-clicking a database sends it to that copy rather than
launching a new one. With the switch OFF double-clicking on a database
closes down an already-open database before opening the new one. Even then
you can load multiple copies of Powerbase by double-clicking on Powerbase
itself and then open a different database in each by dragging the databases
to the icons.

Recalculate on opening affects Composite fields (see 6.2) whose associated
formulae make use of the system variable TIME$. With the switch OFF the
contents of such fields are recalculated only when a record is displayed.
This might not be good enough where, for example, TIME$ is used in a User
function (see 6.3) to keep track of people’s current ages. Selecting the
switch causes Powerbase to scan the whole file and update such fields when
the database is first opened.



Blank record on deletion  If this switch is OFF then deleting a record from
the database merely removes all references to its key(s) from the index(es),
leaving the actual record data untouched in the Database file. Although such
“deleted” records will be overwritten when new records are entered, the
situation may be deemed unsatisfactory from a security point of view since
the “deleted” records can be examined by simply loading Database into Edit.
If the switch is ON deletion causes the relevant record to be over-written
with a blank record.

Keep descriptor with data alters the behaviour of fields as they are dragged
around the screen when designing the record layout.  With the switch OFF you
may drag the data field and the descriptor independently of one another.
With the switch ON this is true only of the descriptor; if you drag the data
field the descriptor jumps to its “normal” position to the left of the data
field as soon as you release the mouse button.

Validate input turns data validation (see Ch 5) ON and OFF.  If you ever
find yourself unable to escape from a field linked to a validation table you
can bring up the Preferences window, deselect this switch and try again.

Display linked table data  Every time the caret enters a field with a link
to a validation table a window showing data from the relevant validation
table row appears to the right of the field if the switch is ON. This is
either useful or infuriating, depending on your point of view. If turned OFF
you can still call up the window for a specific field by double-clicking on
the field with SELECT (see 5.5).

Warn of external deletion  Since deleting data from an External field (see
2.6) involves the deletion of an actual file you will probably appreciate
being warned when you are about to do it. With this switch ON you will be
given a warning and the opportunity to change your mind.

Warn of duplicates  The creation of records with identical primary keys can
be prohibited if so desired (see 11.2.1). Normally, however, they are
permitted. You may, if you wish, turn this switch ON to issue a warning that
such a record is about to be created.

Default action on Return  According to the Acorn Style Guide for RISC OS
typing Return anywhere inside a dialogue box ought to have the same effect
as clicking on the default action button (that’s the one with the yellow
channel border) regardless of which writable icon the caret is in. If that’s
what you want then turn this switch ON. Many users (including the author!)
hate it and prefer the default action to take place only if the caret is in
the last writable icon when Return is typed. Hence the default setting,
which is OFF.

Strip trailing spaces should normally be left ON to avoid unwanted spaces at
the right of data fields. It is easy to press the space-bar by accident when
entering data quickly and you might not notice that a field has one or more
spaces between the end of the last word and the caret.

Balance every <n> records  The need to balance indices and the use of this
option is explained in 10.6.

Remember place in subfile  With this switch OFF a change of subfile leads to
the display of the first record in the new subfile. If you are doing a lot
of hopping back and forth between subfiles to inspect specific records you
might want to select the switch. It is then just as if you had bookmarks in
separate chapters of a book; when you return to a subfile you have
previously visited you will see the same record you were viewing when you
left that subfile.

14.5.4 Save indices (Default: Manual)

Indices are always saved whenever you close a database or quit Powerbase and
only fear of power cuts or system failure (which includes some kind person
switching off your computer!) need make you concerned about saving them
yourself. With the Manual setting nothing happens during normal working
unless you click Force update on the keypad.  Selecting Automatic or Warn
only allows you to type in a suitable time interval (default = 10 min) at
which Powerbase will either issue a warning to save your indices (using
Force update) or actually save them for you.

14.5.5 Application for ImpulseII data-merging

As noted elsewhere (9.2) Powerbase can merge directly into a
suitably-formatted Impression document by simply dropping the document icon
onto the record window. The dialogue box which then appears contains a
writable icon which shows the application with which Powerbase will merge.
This name  is, by default, “Impression”, but may be altered by users for
their own purposes. An application which will receive data from Powerbase in
this way must make use of the ImpulseII protocols as defined by Computer
Concepts. Even if you are using Style or Publisher the name to which these
applications respond is still “Impression”.

14.5.6 Save choices

This section of the window works exactly as it does for CSV options (see
14.4) as do the Load default and Cancel buttons.

14.6  Colours of key fields and linked fields

These may be selected in a window reached by choosing Colours from the
Miscellaneous submenu. The following default colours are used:−

        Type                            Foreground      Background

        Descriptor of key field (inactive)              dark blue
-

        Descriptor of key field (active)                red
-

        Data icon of primary key field  (s)                     -
pale yellow

        Data icon of field linked to validation table   dark green
-

Clicking with SELECT on the descriptor and data icons within this window
makes either the foreground or background (depending on the setting of the
two radio buttons) cycle through the available colours. Clicking with ADJUST
cycles through the colours in the opposite direction.

Apply allows you to see the effect of the changes and Defaults enables you
to return the colours to what they were before, provided you haven’t clicked
on Save choices. The latter applies the new colours and saves the changes so
that they are effective next time the database is used. Different databases
may have different colours.

14.7  The Config file

Inside the Powerbase application directory is a sub-directory called
Resources. The file Config, which will be found there, determines certain
aspects of the program’s operation which will seldom need changing. Changes
made to Config take effect only when Powerbase is next loaded. If you load
the file into Edit you will see lines which determine:−

•       maximum number of fields per record (default = 100, maximum = 127)

•       maximum number of subsidiary indices (default = 10)

•       maximum number of validation tables (default = 10)

•       maximum number of pop-up menu fields (default = 3)

•       maximum number of columns in a validation table (default = 20)

•       whether or not submenus off the icon-bar menu open on the left
instead of on the right as normal.  This feature of RISC OS 3 avoids the
overlapping submenus which can occur but is so seldom seen that most users
can’t cope with it at all!  Put YES, instead of NO, at the start of the line
if you want the icon-bar menu to work like that.

•       background colour of record window.  Default (1) is pale grey.

•       whether or not keyboard is placed in caps lock mode when user is
being asked to input a password.  This is to avoid annoying users who set up
password-protected databases with earlier versions of Powerbase which
allowed only uppercase letters in passwords.  Such users will wish to place
YES at the start of this line.  Current versions of Powerbase allow both
upper and lowercase letters and users will not want caps lock to be forced
on.

When altering Config be sure to leave a space between the number (or YES/NO)
and the explanation.

14.8  The Messages file

This too is a text file in the Resources sub-directory.  It contains all the
error and warning messages used by Powerbase and all the messages for use
with the Acorn interactive Help application. The wording of these may be
altered if you wish.  Many error messages contain the string “%0” and
possibly “%1” and “%2”. Items of data are substituted for these when the
message is printed so it is important not to omit them or alter their
logical placement within the message.