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Ch 1 - Introduction to Powerbase

1.1 Description and installation

Powerbase is a database management system for use with RISC OS computers. The information in this documentation applies to Powerbase v.9.74, which may be run under everything from RISC OS 3.1 onward. Earlier version of Powerbase lack many of the features of v.9.74 and users of such versions are strongly urged to upgrade.top of page

1.1.1 Installation
You may receive Powerbase and its accompanying documentation and sample databases in compressed form as a set of zip files. These need to be unzipped (de-archived) before you can use them. The following procedure is suggested:

  1. On your hard disc create a new directory called Powerbase and open it.
  2. Run the copy of !SparkPlug supplied on the distribution disc.
  3. Double click on one of the files you wish to unzip. A window will open showing the contents of the file.
  4. Select all the objects in the window and drag them to your newly-created Powerbase directory.
  5. Repeat steps c and d until you have de-archived all the material you require.

1.1.2 Tutorials
Two tutorials are provided. If databases are completely new to you we recommend you to work through the Quick Tutorial which is based on the simple address-book database !Friends. If you are somewhat more experienced but are using Powerbase for the first time you will probably find the Main Tutorial, using the !Elements database, more appropriate.

1.1.3 Disclaimer
No warranty, express or implied, is made about the suitability of Powerbase for any purpose. We cannot be held responsible for any loss or damage due to the use of this software. All enquiries, requests for upgrades etc, should be directed to:
  Powerbase Support
  112, Keighley Road
  Colne
  Lancashire
  BB8 0PH
  Tel: (01282) 866835
  email: dhaslam@boulsworth.co.uk
  website: www.boulsworth.co.uk/pbase/

When requesting an upgrade by post please enclose four first-class stamps to cover cost of disc and postage.top of page

1.2 Starting and ending a work session

1.2.1 Loading Powerbase
Double-click on the Powerbase icon in a directory window and the program will load and place its icon on the iconbar. The words "No data" will appear under the icon indicating that no database is open yet.

1.2.2 Opening a database
A database may be opened for use by either: What happens next depends on whether the database is password protected or not. If no passwords have been defined (as is the case with all the sample databases on the distribution disc) the Record window will open and the name of the database will appear under the Powerbase icon.

A password-protected database will display the Access window in the middle of the screen requesting you to enter a password and perhaps even a personal user I.D. as well. The window has an Open button which should be clicked with SELECT when you have entered the required information. There is also a Cancel button which removes the window from the screen without further action. Passwords and I.D.s are case-sensitive and, if incorrectly entered, result in either a "Password not known" or "Access denied" message. After three successive incorrect entries Powerbase will close down and remove itself from the iconbar.

1.2.3 Closing a database
a database can be closed by: If you have made any change to the database while it was open the disc will be updated automatically so that your changes are not lost, regardless of which of the above three methods of closure is used. (Note)top of page

1.2.4 Backing up a database
backup/png When you have a database open look at the Tool-pane attached to the left edge of the Record window and find the Backup button. Before you can use the backup feature you need to tell Powerbase where the backup copy of the database is to be saved. To do so click the Backup button with ADJUST. This opens the Backup choices window. Decide which directory you are going to use for backups and drag the directory onto the large down-pointing arrow. Its pathname will then be displayed in place of <no directory>.

You may choose to keep 1, 2 or 3 "generations" of backup and Powerbase will move backed-up copies into subdirectories Older and Oldest where required.

The option button Back up on closing may be selected to force automatic backup when the database is closed, but backup won't occur if the database is unchanged. There might also be times when you want to bypass this setting and simply close the database without backing up. You can do so by holding SHIFT down while you choose Close database.

When you have made your choices they need to be saved somewhere. If the choice of directory and other options apply to one database only it is best to save the choices inside the database itself, so see that the in database radio button is selected as shown in the illustration and click Save choices. If you intend to use the same choices for all your databases they should be saved in Powerbase. The remaining option (for User) might have different wording or not be available at all depending on which version of RISC OS you have. A full explanation of these options will be found in 14.1.8.

Once the backup choices have been established a click with SELECT on the tool-pane Backup button will back up your database. You can always open the Backup window again with ADJUST if you want to change your choices. Notice also that the window displays the date and time of the most recent backup, if any. The Open directory button provides rapid access to your backed-up databases if you need to retrieve them. If a backup copy of the database exists clicking Restore saved database will give you the option of restoring it, overwriting the current copy. If there is more than one generation of backup you will be offered the choice of which one to restore.

There might be occasions, especially during the development of a new database, where you want to save your work at frequent intervals and three generations are not enough. To meet this need a fourth option, T (Time stamped), is available. This works somewhat differently from the generational approach. When the Save choices button is clicked Powerbase will create a new subdirectory in your designated backup directory. It has the same name as your database but without the initial "!". From then on, every time you click Backup on the tool-pane a new subdirectory will be created inside the one named for the database and a copy of the database will be placed in it. You may create an unlimited number of these "sub-subdirectories" and the name of each is the time and date at which it was created. If you need to retrieve one of these time-stamped copies of your database click Restore saved database as usual but, owing o the large number of copies there could be, you won't be able to make the restore happen automatically by simply clicking a button. Instead, the subdirectory named for your database opens showing the time-stamped locations of the copies from which you can make your choice and copy the saved database back after removing the current version.

1.2.5 Quitting Powerbase
Choose Quit from the iconbar menu. You need not specifically close your database first; any changes made to it will be saved before Powerbase quits.top of page

1.3 Obtaining help

1.3.1 Using the Acorn Help application
When you are first becoming acquainted with Powerbase you may find it useful to load Acorn's Help application. Powerbase's iconbar Information window and main menu Subfile control window each have a blue button (like the familiar tourist information sign) which will launch the Help application for you. Moving the mouse pointer over Powerbase's numerous windows, icons, and many of its menus will then give a brief description of the purpose of each.

1.3.2 Using PbaseDoc
Comprehensive help is available by clicking the PbaseDoc button on the Information window accessed from Powerbase's iconbar menu. If PbaseDoc has been "seen" by the filer it will be run, giving access to the complete tutorials and reference manual.

1.3.3 Emailing Powerbase Support and accessing our website
The iconbar Information window has buttons called Web and Email. Provided that the filer has "seen" your browser, clicking on the Web button will load it, if it's not already loaded, and insert the correct URL for our website from which you can download the latest version of Powerbase, its documentation, and a set of sample databases and script files. Similarly, if the filer has seen your mail program, clicking on the Email button will bring up a blank email with the correct email address for Powerbase Support.




Note

There is one circumstance where this is not possible and that is when you are running a database from the RAM disc. Switching off the computer or quitting the RAM disc will, of course, result in loss of data. When you close a database on the RAM disc therefore, Powerbase will warn you to back it up to a more permanent medium. (back)

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