A tCursor is simply a pointer to a specific record of a specific table, and
lets you access everything about the record. You open it on the table and
then move it to the record using locate() or qlocate() (the latter uses an
index for extra speed); from there you can use the tCursor to read any
field. The scan/endscan loop moves it through the entire table top to
bottom, and can take a selection criterion as well.
For a flat file, just point a tCursor at it and scan through it. For a
relational database, point one tCursor at the parent, and a second one at
the child. Scan the parent table with its tCursor. For each record you hit,
read the child table's local key into a variable, and then tell the child
table's tCursor to qLocate it. Now you have everything you need to
textStream the data to a file.
A form based approach is possible, but would be much slower to execute (by
at least one order of magnitude, and probably two), and would be tricker to
write (because you'd have to deal with the form's object hierarchy).
As for OPAL resources:
1. The online help is the best place to start: Help/ObjectPal Reference,
and Help/Objectpal Tutorial. The reference starts with a complete
explanation of the language. Start there, then look up "tCursor Type" and
"textStream Type" in the index.
2. When you use the embedded OPAL editor, you can put your cursor on any
command, hit <F1>, and get the help page for that command. These pages are
pretty good, with helpful examples and links to similar commands.
3. Your best resource is the community of enthusiasts and developers who
runs this and other Paradox news groups. Their web page is
http://www.thedbcommunity.com/
and it contains many articles and archived news groups.
4. AFAIK, there are no third party manuals currently in print. The easiest
to find is Mike Prestwood's Paradox 9 Programming, which despite its age is
almost completely current. You can read chapters from it on Mike's site,
http://www.prestwood.com/ASPSuite/kb/browse.asp?tid=103
HTH,
Jim Hargan
On Tue, 01 Jul 2008 19:11:06 +0200, Michael.Ruehling.TakeThisOut@t-online.de wrote:
> On Mon, 30 Jun 2008 18:10:33 -0400, Jim Hargan
> wrote:
>
>>On Mon, 30 Jun 2008 21:37:23 +0200, Michael.Ruehling.TakeThisOut@t-online.de wrote:
>>
>>> Hi,
>>> I am using Paradox 9. Thesedays I am trying to convert all of my
>>> Lists into XML-Files to display them via XSL.
>>> Has anybody tried to write an XML-Export-Filter -Function or
>>> something like that in ObjectPal?
>>> Anything is helpful.
>>
>>I wrote an OPAL system that creates valid XHTML web pages from text content
>>stored in Pdox tables. This is XML, but probably not what you are looking
>>for. However the principle is simple:
>> - use tCursors to find the datum you want to write;
>> - store it in a string variable (all XML data are strings);
>> - add the XML tags to the start and end of the variable; and
>> - textStream it into the XML document.
>>
>>I've been using it successfully for five years or so. I created my web site
>>with it, and I create lightboxes for clients with it several times a week.
>>
>>HTH,
>>
>>Jim Hargan
>>www.harganonline.com
>
> Hi,
> this is what I want. But I want to do it automaticly (?) for all of
> my tables without manual interference.
> e.g.:
>
> [PSEUDOCODE]:
>
> openTable(char Name);
> while (!EOF)
> {
> STRING Var = add(XML_VARIABLE_START, datum, XML_ELEMENT_END);
> writeFile(openTextFile, Var);
> }
> closeTable();
>
> So far it complies with your Thought, except for the tCursor to find
> the data.
>
> By the way: Is there any good book/resource for OPAL?
>
> Thanx
> M. >> Stay informed about: ParadoxFile to XML 
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