#21 Port from Access

[Anonymous]

This is a biggie. But it would be terrific to be able
to port a MS Access application to a Gambas app. Maybe
a good intermediary would be an xml document describing
the Access forms, reports, queries, macros, and
modules? The trickiest part would be translating VB
into GAMBAS Basic. But this would be the killer app --
the one thing OpenOffice.org doesn't do that MSOffice does.

[Ron O.]

Logged In: YES
user_id=865563

I was on sourceforge and look in the ToDo list. (12 sep 2003)

The entry about port M$Access looks nice to me but
I already forsee big problems.
All information is stored in a *.mdb file wich is a format
of M$ designed and owns.

Modules & Classes:
Can be exported as text from Access.
Need much changes because it is working on a namespace
wich
mostly not is seen. I think this is a leak of Gambas.
Syntax structure should be convertible, that was my C++
example could handle. My php version has more but is also
not ready to do it.

Queries:
Can be save with cut and paste from the designer.
The 'Save' menu command saves only the result of the
query.

Tables:
Like the Queries.

Forms:
This is the biggest problem.
They are stored as objects in hidden system tables and give
no acces without password, secret from MS, so if you want
that
you must readout the .mdb file with a binairy file editor,
make a analize of the content structure, translate the tokens
to the object names and many more to get something as a
form
file. Also the controls have properties like 'OldValue',
Field, Binding etc. in addition to the standard controls
from windows.

Reports:
I do even not think about that.

If the Access aplication also build tables and queries in runtime
then it is working with a DAO object/namespace. In this case
the
current db object is total nonsence, unusable. Structure is:

Databases,Database,Tables,Table,Fields,Field

myFieldValue= DAO.Databases("MyDB").Tables("MyTbl").Fields
("MyField").Value

For ADO there are also
Connections,Connection,Commands,Command etc.

Consider also that all objects are default byref instead byval.
This makes it a hell of a job todo, special the forms if you
want a copy of them.

The only thing Gambas can support native is subform objects.
I did a port from Access to VB of the workflow controller I
made
as job and there was it already difficult to emulate some of
the
events in the forms. Data binding of the controls like Access
was more or less out of the box, QTcontrols or Gambas don't
have that.
I'm afraid to ask Benoit to add some events, even if the are
supported by
QTcontrols. For properties my exmaple for missing proprties
can do help.

Ron

[Benoit Minisini]

Logged In: YES
user_id=29457

I can't automatically convert a VB app to Gambas, so... There are
horrible behaviours in the native VB language that make this task
impossible ! After having used VB for years, I can't decide if Microsoft
did that on purpose, or stupidly...