Zugg Software :: View topic

Posted: Sun Jul 18, 2004 4:11 am

The latest Alpha version of zApp (previously called Zeus). This is the new application development environment being developed by Zugg Software. For a Limited Time, Pre-order zApp for $25. That's HALF PRICE of the eventual public version.
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New features include: Database connections and data aware controls, new demo programs for viewing any database.

This version has the following new features:

1) Database connections! New components include:
<CONNECTION> To specify a database
<DATASET> To specify a table or SQL query (ADO RecordSet)
<DATASOURCE> Connects DataSet to visual controls

2) All database controls with values have a new "DataSource" and "Field" properties to tie them to databases. This includes <EDIT>, <MEMO>, <CHECKBOX>, <COMBOBOX>, <SPINEDIT>. The <GRID> field has the "DataSource" property and can display an entire table at once. The <COLUMN> Field property can be used to restrict which fields are displayed in the grid.

3) New ListStyle of <COMBOBOX> of "Tables" for displaying a list of tables in the current Connection object.

4) New demo program DBVIEW.ZML. This demo has a Connect button which calls the Prompt property of the Connection object to prompt you for a database connection. This displays the standard Windows database selection dialog. ANY database supported by ADO in Windows can be opened. When the database is connected, the Combobox next to the connect button is populated with the list of tables in the database. Select a table and it will be displayed in the grid. Any SQL command can be placed in the edit field. When you tab out of the edit box, press Return, or click the Query button, the SQL query will be executed and the results shown in the grid.

5) New demo program MAPVIEW.ZML. This is a more specialized database demonstration. This program has a File/Open menu for opening a zMUD (or zMapper) *.MDB Map database. When the map is opened, a list of rooms in the map is shown in the grid on the left. On the right are various database controls for editing the record of the database. It shows examples of an <EDIT> field (for the name), the <MEMO> field (for the description), several <SPINEDIT> controls for X,Y,Z, a <COMBOBOX> for the LabelDir field showing a simple combobox, another <COMBOBOX> for the ZoneID which is set in Lookup mode to lookup the name of the zone given the ZoneID. In the toolbar is a combobox that shows a list of zones in the file. Selecting one of these zones sets the Filter for the dataset so that only rooms in that zone are shown. The Filter edit box can be used to specify your own filter expression.

The one problem with all of these demos is that the <GRID> component that I'm currently using is REALLY SLOW! I am well aware of this problem. I am consulting with the 3rd party vendor that makes this grid component to see why it is so slow. If they can't fix it, then either I will try to fix it myself, or I'll use a different vendor. From what I can tell, the grid is really stupid and seems to load the ENTIRE database table into the grid data cells. Not only does this take up a lot of memory, but it's very slow. On top of that, even scrolling the grid is slow (which is shouldn't be if everything is already preloaded into the grid). Fortunately, the Zeus architecture doesn't care what kind of grid component I use, so swapping components won't be very painful. This particular 3rd party vendor has been a huge disappointment so far. Their web site and advertising make their component set look really good, but it's only when you actually start using it and dig into their source code that you find how bad the code is. So far I'm only using them (TMS is their name btw) for the Grid and Label (with basic HTML support). So I haven't invested much in them yet.

Other than the speed issue (and after all, this is still an ALPHA release), I think the database components work pretty well. I'd be interested in hearing about any problems you might have with the particular ADO/MDAC setup on your own computer. I already found/fixed a long-time bug in Delphi dealing with MDAC 2.7 and above that even zMUD didn't have fixed which might have been the cause of some random access violations in the mapper.

Take a close look at the demos to see how they work. When you specify a Field property, it automatically looks for a DataSource to connect with it, so the DataSource property of the controls is optional.

I think with the database stuff mostly working, it's probably really time for me to start writing more documentation. I know it's hard to play with this stuff with no documentation and just a bunch of demo apps.

Next week I am busy with some other stuff, so it will be August before you see the next update along with more documentation.

Feel free to post bug reports to the new Bug Tracking system if you find something can be reproduced and you think it's a bug. Otherwise just discuss it here in the forums.

To download the new version, go to the main www.emobius.com site.

Have fun!!