Dave Alessi

Subscribe to Dave Alessi: eMailAlertsEmail Alerts
Get Dave Alessi: homepageHomepage mobileMobile rssRSS facebookFacebook twitterTwitter linkedinLinkedIn


Top Stories by Dave Alessi

p> Have you ever used a grid DataWindow to maintain a table in which columns use DropDownDataWindows for selection, but one column's choices are dependent on another? It's a pretty common scenario, but one that's not so simple to code. For example, let's assume we have a state table (see Table 1) and a city table (see Table 2) in our database, both using code to represent their textual values. My two DropDownDataWindows are coded to use a Display column of city or state, and a Data column of code. What's required in the application, of course, is that when you change the State column, the City column shows only cities within that state (see Figure 1). Figure 1: At first glance it looks pretty simple. My first thought was to put some code on the ItemChanged event for the State column, to do a filter on the city DropDownDataWindow. A different approach would be to d... (more)

Personalized Grid DataWindows

One of the really neat features of the grid DataWindow is its ability to move and resize columns. This allows users to customize their view and make better use of the screen. Trouble is, once you alter the DataWindow and get it just the way you like it, the format information is lost when you close the window and reopen it. Wouldn't it be nice if you could save this format information? It would be nicer still if users could have their own personal preferences, which would "follow them around" based on their logon. This article discusses an approach to implementing this feature i... (more)

Database Connectivity with Applets Using PowerJ

My company, Internal Systems, sells a commercial application built using PowerBuilder. Our application is used by companies of varying types, and we found it necessary to support multiple back-end databases to accommodate the needs of our customers. In PowerBuilder, we use ODBC as our portability layer, and have found that we can build a single executable that will work across our four major platforms (Oracle, Sybase ASE, MS SQL, and SQL Anywhere) and possibly others. Like many other vendors, we were faced with the problem of delivering a thin-client version of our product, part... (more)

Personalized Grid DataWindows

One of the really neat features of the grid DataWindow is its ability to move and resize columns. This allows users to customize their view and make better use of the screen. Trouble is, once you alter the DataWindow and get it just the way you like it, the format information is lost when you close the window and reopen it. Wouldn't it be nice if you could save this format information? It would be nicer still if users could have their own personal preferences, which would "follow them around" based on their logon. This article discusses an approach to implementing this feature i... (more)

Filtering Grid Lines

p> Have you ever used a grid DataWindow to maintain a table in which columns use DropDownDataWindows for selection, but one column's choices are dependent on another? It's a pretty common scenario, but one that's not so simple to code. For example, let's assume we have a state table (see Table 1) and a city table (see Table 2) in our database, both using code to represent their textual values. My two DropDownDataWindows are coded to use a Display column of city or state, and a Data column of code. What's required in the application, of course, is that when you change the State ... (more)