Creating Processes - Oracle

Processes, like almost anything else in HTML DB, are created with a wizard. The wizard for page-level processes is started either from the Add icon in one of the two Processes sections on the Page Definition page or through the Create link on the Developer’s Toolbar (selecting the Page Control on This Page option and then the Process option). In the first step of the Create Page Process Wizard, you must select from one of the eight different types of processes available (see Figure 13-1).

The wizard for application-level processes is started with the Create button from the Application Processes section of an application’s shared components. With application-level processes, you will not have to select a process type because the only type you are allowed to create as an application-level process is a PL/SQL type process. The eight different types of processes are

Figure 13-1.  Process types in the Create Page Process Wizard

briefly described in the following table. The remaining steps in the process-creation wizard vary depending on the process type you select.

The path of the wizard will vary depending on the type of process you choose to create. A number of fields will be entered for most processes. In the Name field, you provide a descriptive name of the process to give other developers an idea of what the process does. The value you enter in the Sequence field is used to determine the order in which processes will be evaluated within the same process point. The Point field is used to specify a point in page rendering or page processing at which the process will be evaluated. Here are the possible points:

• On New Instance – After Authentication
  
• On Load – Before Header
  
• On Load – After Header
  
• On Load – Before Regions
  
• On Load – After Regions
  
• On Load – Before Footer
  
• On Load – After Footer
  
• On Submit – Before Computations and Validations
  
• On Submit – After Computations and Validations

In almost all the paths through the Create Page Process Wizard, after you select the type of process you want to create, as shown earlier in Figure 13-1, you will be presented with the process’s Type field. The value of this field will be the type you selected. In most cases, you won’t want to change its value. However, when you select to create a PL/SQL type process, this field will default to the value “PL/SQL anonymous block.” You may wish to change the Type field to “PL/SQL DBMS JOB (runs anonymous block asynchronously).” This allows you to run the process in the background. This is ideal for long-running processes where the user does not need immediate feedback from the process.

The values entered into the Success Message field will be displayed if the process is evaluated successfully and the following page has the #SUCCESS_MESSAGE# substitution variable used in the page template. The value entered into the Failure Message field will be displayed if the process fails. You can make a process conditional by selecting a button for the When Button Pressed field and/or by selecting a condition type and specifying values for Expression 1 and Expression 2.