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Bob Hendry

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Top Stories by Bob Hendry

JBuilder Data Express controls enable JBuilder developers to use prebuilt objects to provide the user with an interface in which to view and manipulate data. For the most part, the use of Data Express components simplifies our task of programming data access functionality into our applets/applications. One drawback of using these components is that you're restricted to using only functions and changing properties that are supported by that specific control. In other words, although JBuilder simplifies your task, you can use only prewritten functionality. What if you wanted total control over your data? What if you wanted to control every aspect of how your data is formatted, displayed, edited, and up- dated? The answer to this is knowing how to use the native Java JTable. Mastering the use of this class is your key to exercising total control over data within your ... (more)

Dynamically Creating DataWindow Objects

Objects can be added to your DataWindow programmatically via a Modify statement. In my opinion, the dynamic creation of objects within a DataWindow has been a highly underused feature. Dynamically creating (or destroying) objects within a DataWindow has many advantages such as: Dynamically changing the content If a printed DataWindow varies in appearance from its visual presentation The syntax for creating objects within DataWindows can be daunting; no wonder it's not used that often. Before I go into more detail, it's important to know how objects are contained in a DataWindow i... (more)

Dynamic SQL

From the beginning, the DataWindow has been a powerful client/server control. What has set it apart from competing products is its ability to create SQL. In reality, the DataWindow is a SQL-generating machine. By keeping track of row and column statuses, the DataWindow is able to generate the correct SQL statement to UPDATE, DELETE, or INSERT rows into a database. In most instances, the developer is oblivious to the SQL generation; all that's needed to unleash all this functionality is to issue a simple update function. However, DataWindows can take SQL only so far, as their use ... (more)

Using The Jtable

In Part 2 I continue my discussion on the use of the JTable. (Part 1, "Mastering the JTable," can be found in the January issue of JDJ, [Vol. 6, issue 1].) I'll briefly review the three major classes you'll need while working with data within the JTable. 1. JTable: Controls the visual presentation of the data, however, it has limited control over where the data comes from. In the simplest of circumstances, the JTable can populate itself with data only if the data is static and doesn't come from a database. In the above case, it can be used without any supporting classes. Usuall... (more)

Using the Jtable

In Parts 1 and 2 of this article (JDJ, Vol. 6, issues 1 and 7) I discussed how to use a JTable with a table model and showed how much work is involved getting a JTable to work with data. This is quite a departure for veterans of other fourth-generation languages who may be used to developing in Visual Basic or PowerBuilder. Both these languages have intelligent controls that keep track of the data as the user is manipulating it. These controls can then determine how to handle database changes such as inserts, updates, and deletes. Java doesn't have any built-in functionality. Re... (more)