Just an idle note about issues with DP
I still find that cascading deletes and updates do not work completely
reliably. Good enough to base applications on - but I know that yearly I
will have to recompute.
I also find that the ::j is still not rock solid in a network environment. I
still have instances with duplicate records, or problems with rollbacks. Ie.,
f9 create a record, F1 cancel, more or less simultaneously done by two users.
But I am not complaining. I love the product.
You know, maybe Ralph (or you) should set up a 3 day seminar Web enabling Data
Perfect. I think we could get 20 users or so. Air fares are cheap right now -
and miami is 80 degrees.....
From: [email protected]
To: [email protected]
Date: Mon, 16 Mar 2009 06:54:14 +1100
Subject: Re: [Dataperf] HTML
Hi Chris,
DP has been and still is an extremely good product. But you are right moving
into the web world with DP does take a lot of work…
The benefit I now find from DP is ironically the user-interface (which the end
user now doesn’t get to see). The DP interface for building an application is
great. You can put together complex databases in a matter of minutes and then
know that your building is rock solid. Even though the panels are themselves
not visible to the user, I still put up all the visual elements I would for a
conventional DP applications, so the panel sort of becomes the graphical and
textual documentation of the data structures. In an instant I can see how the
fields of information fit together, the links the lookups, and when I am
writing reports I get to see the “documentation” as I go.. If I ever need to
go back and see how a field fit its into a report Shift-F3 and I see it in the
context of my documentation. Although it is a bad practice, you can throw a DP
application together while you are still conceiving it. Other paradigms require
you to do lots of planning before can even start building.
The other benefit I still really like about DP is its reliability. Unless I
have done something really silly, you just never have a problem with it. I
have just had to go through a number of old Microsoft Access projects where I
had used Microsoft supplied ActiveX components, the components were part of VB6
and also the Office 2000 Developer Kit, and worked fine for donkeys years
surviving even upgrades through Windows XP, Vista, Office XP, Office 2003 and
Office 2007, only to have them all break a couple of weeks ago when Microsoft
decided as part of a Windows Update security upgrade for Internet Explorer to
“turn off” (using a ‘killbit’) these ActiveX components because someone had
found a way of exploiting them in IE. Some of these applications had not been
touched for years and years but can be so easily broken by Microsoft. I know
that iof Microsoft kills off the environment for running DP, that I can easily
move it across to Linux.
Regards
Brian
From: [email protected] [mailto:[email protected]]
On Behalf Of Chris Pedersen
Sent: Monday, 16 March 2009 5:46 AM
To: [email protected]
Subject: Re: [Dataperf] HTML
My expectations? Perhaps a bit of an misstep.
I dont' have any real expectations that WinDP will happen, either. But its a
shame as I think it should.
DP owed a lot of its success to the fact that it had an easy userinterface that
allowed easy db creation - with great speed. While I am aware that one can
make an html interface to dp - and I have tried it a couple of times - it
simply requires too much programming - for me and I would say most people.
What I would look for would essentially something to put the standard "windows"
look as a dp front end. Elevator boxes, mouse support. And possibly better
data exchange.
But I don't think voicing an opinion (offering input) changes one tittle
whether the product is developed or not. People ignore my opinion all the time
=).
Best
Chris
From: [email protected]
To: [email protected]
Date: Sun, 15 Mar 2009 14:01:55 +1100
Subject: Re: [Dataperf] HTML
Hi Chris,
Your expectations are one of the reasons that I do not think WinDP will ever
be, or will ever be in the form that people will want or expect.
In the DOS age applications generally did not need to support communication
between other programs, or to share services with other programs, or to have
functionality outside what the original developers planned. WP’s Shell was way
ahead of its time in this respect, but so small compared to the extremely wide
range of functionality that software is expected to have these days. For DP to
come out in a Windows format with all the functionality that would be expected
I think is extremely unlikely.
However, DP for DOS as a specialist database still is extremely valuable and
certainly fits into modern day Windows, MAC or Linux applications; just not at
the front end on these machines. In fact the way DP for DOS works it forces
you to go into the most modern means of using databases. Although I still write
desktop applications in Microsoft Access the typical desktop database
application is all but dead whether it be Windows or DOS.
DP well fits into what is known as a multi-tiered or n-tiered architecture.
n-tier is a client-server architecture where the end-user client application;
the application processing and the database management are separate processes.
The tasks of a tier is generally performed in physically independent piece of
software.
On in the other hand Microsoft Access and other desktop file databases
including the original DP paradigm, the user interface, application processing
and database management all seems to coexists in what is better described as a
multilayered approach, where the tasks of each layer exist are performed within
the same program.
The problem with the multi-layered approach is that the expectations that
various prospective users will have for each layer are now so vastly different
that it really exceeds the capacity of any vendor to fill its needs, and as
well as that the internet has brought a networking model that is not supported
by this multilayer approach.
You often hear people talk about other desktop multi-layered applications being
used on the web, such as “we just use Microsoft Access as a backend database”:
When they do this, they are no longer using two of the Access layers, but
instead use one layer purely for database management. They then write all the
other functionality with a user-interface (often HTML) and a middleware
component (often PHP, ASP or VB.NET). They write protocols whereby one layer
can efficiently communication with the next layer, and do not need to be
concerned with how the nonadjacent layers work.
Microsoft Access in this type of database roles works ok, but it does have many
limitations, for a start it’s not a great multi-user database manager - its
locking mechanism gets into too much trouble. Used this way it lacks many of
the features that makes it such as easy desktop program, but it also misses out
on some other important feature that a desktop fil database does not need. In
the database world you really need a program that can run Views. Stored
procedures and Triggers. Found in modern database managers such as Microsoft
SQL server, Oracle, PostgresSQL etc. Microsoft Access can only either return
table data or handle simple Views..
Views are queries where a either a subset of data is returned or where tables
are joined, often using SQL SELECT statements. Stored Procedures are often a
sequence of SQL queries that in combination can perform tasks such as inserting
data into multiple tables, deleting data or for executing other programming
code. Database triggers is procedural code that is executed in response to data
being added, deleted or changed.
In web driven DataPerfect you basically forego the user interface layer. The
interface for other adjacent layers is via the Transaction Log for input and
via reports for business logic and output.
So in comparison to say a SQL database, in DP a View is implemented by way of a
simple database report, and a Stored Procedure is just a more complex report.
Although DP doesn’t have a good analogy to Database Triggers there are a number
already built in, which in other environments you would have to carefully
built. For example, keep-a-total’s in other database systems need to be
implemented as a set of relatively complex procedures, whereas in DP it is just
easily done through Panel design . Similarly cascade deletes are more
cumbersome in many environments as are calculated fields.
One feature which is lacking in DP is the ability to create Pass Through
Queries, where the code to be executed is crafted at the client application,
and pushed through to the database program. However unless you are very careful
you can often create security problems, by allowing client programs unfettered
access to the data, so if you do then you have to build far more complex and
robust backend applications.
You really have no limit to the types of applications that can be built with
DP, and the types of front end applications. The client programs can be web
deployed HTML, Flash, Flex, or they can be stand alone applications such as VB,
VB.NET, Java, Adobe AIR etc. DP’s reports can often be far more useful than
Stored Procedures , and so entire business logic ca be built with reports,
making it one of the middleware tiers. You do however need another tier to
handle the client requests, and output back to the client; I use Perl for this.
I generally build my DP applications as web applications, but you could quite
easily build applications with other applications in the front end. You do not
need a web server to create Windows applications, it would be quite possible to
build say a desktop application using Microsoft Access with DP in the
background as the database manager. It would probably take a lot more work than
just using Access built in JET databases but it could be done.
At the moment I feel like Robinson Crusoe, I wish others would start having a
go at using DP for web databases. It would certainly be great to be able to
draw on other peoples experiences with it, and to get a collective body o
knowledge and expertise around it
Bye
Brian
From: [email protected] [mailto:[email protected]]
On Behalf Of Chris Pedersen
Sent: Sunday, 15 March 2009 12:09 AM
To: [email protected]
Subject: Re: [Dataperf] HTML
I think for many reasons it would be incredibly useful to be able to execute
foreign code.
A couple of formats:
Click to execute the content of a field -
Click to execute an app defined on a field
From: [email protected]
To: [email protected]
Date: Sat, 14 Mar 2009 07:32:00 -0400
Subject: Re: [Dataperf] HTML
If user is using windows xp/vista, shell macro can execute IEXPLORE c:\help.htm
which loads a page called help.htm. DPMouse can launch the macro. Or you can
load a text editor with text help if you don't like html.
From: [email protected] [[email protected]] On
Behalf Of Chris Pedersen [[email protected]]
Sent: Friday, March 13, 2009 9:39 PM
To: [email protected]
Subject: Re: [Dataperf] HTML
Yet, it seems like an easy and important component in the transition to WinDp.
Such a product would have to support XML/HTML. Allowing DP to use this as a
help documentation would be a good first step.
From: [email protected]
To: [email protected]
Date: Sat, 14 Mar 2009 10:28:01 +1100
Subject: Re: [Dataperf] HTML
Hi Chris,
I don’t think you will get any luck with DP itself on this, however I have
heard of a DOS TSR which creates hyperlink of whatever looks like a valid URL’s
on the screen…
I have just gone for a quick search for it on my PC, as I thought I had
downloaded it but alas no luck. I can’t even remember what it as called, and I
didn’t even try it, but I thought it could be something useful…
It is probably worth searching Google for it. I had a quick search then and
couldn’t find it, but I think it was on a site with a large number of other DOS
utilities.
Bye
Brian
From: [email protected] [mailto:[email protected]]
On Behalf Of Chris Pedersen
Sent: Saturday, 14 March 2009 9:25 AM
To: [email protected]
Subject: [Dataperf] HTML
I apologize if this is already covered territory.
Oft times, I find the required help for a panel exceeds the dos capabilities or
convenience of dataperfect.
Two questions/suggestions; the first is simpler, the second more of an
extension to the first.
1. Is it possible to pass a url in the help panel as a way of passing
additional help for the database - procedures (or an index code, so it jumps to
the appropriate page).
2. Would it be possible to link an external web page to a field: Ie., when a
person clicks on a field, the sidekick browser gets passed a webpage.
That webpage has all the help required for the field.
Chris
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