HP 3000 Manuals HP 3000 Manuals
Appendix B HP ALLBASE/4GL Versions Versions This appendix describes the procedures for creating and maintaining versions of HP ALLBASE/4GL applications. A version is a set of additional parameters that operate in conjunction with a base application. When HP ALLBASE/4GL runs a version, it effectively runs a modification of the base application. Typically, you would use a version to provide an application that has been modified to suit the needs of a particular end user, or group of end users. A version is not a modified copy of the base application. Instead, it's a set of parameters that represent the difference between the base application and the modification that you want to present for the selected users. A version cannot be run unless the base application exists on the same HP ALLBASE/4GL system. Also, versions cannot be unloaded or loaded without the base application. Defining Versions Defining a version and the list of eligible developer names and end user names for the version is a system administrator task. The system administrator can assign a development security code for a version. The HP ALLBASE/4GL Developer Administration Manual describes these procedures. Developing Versions For the most part, the techniques for developing versions with HP ALLBASE/4GL are identical to the techniques for developing any other application. All the facilities of the HP ALLBASE/4GL developer are available to you while you are developing a version. To develop a version of an application, sign on to HP ALLBASE/4GL as normal, and then enter the version name in the Application or Version field on the HP ALLBASE/4GL sign-on screen. While you are developing a version, all the components of the base application are accessible, although they appear in secured form. Although base application components are accessible while you are developing a version, a component does not become part of the version unless you press the Commit Data function key. There is no need to commit a component from the base application in a version unless you modify the component. To define a modified component for a version, call up the component of the base application on the appropriate definition screen and enter N in the Secured field if the item is secured. You can now make any changes that are required, and commit the component as part of the version by pressing the Commit Data function key. You can also use the appropriate definition screens to define new components for the version. The catalog copying screen in the utilities menu allows you to copy components from other applications or versions. When you define a new or modified component for a version, (for example, adding a further option to a menu and the necessary screen and logic to support the option), HP ALLBASE/4GL stores the additional information with the version. If you modify an existing item to create a new item for the version (for example, adding some further fields to an existing screen) HP ALLBASE/4GL takes a copy of the original item from the base application and stores the modified item with the version. With the exceptions listed below, any subsequent changes made to items in the base application are automatically reflected in versions of the application, provided a modified copy of the same items doesn't already exist in the version. If you have defined a modified item in the version, changes to the same item in the base application have no effect on the item in the version. Limitations Under some circumstances, changes to the following items in the base application will not be reflected in versions of the application: * Validation ranges. * Validation tables. * Alphanumeric constants. * Numeric constants. * Variables. * Calculated items. * Data file definitions. * Work area definitions. * Scratch-pad name declarations. HP ALLBASE/4GL stores these items in common internal lists. If you make a change to any one of these items in any particular type, HP ALLBASE/4GL creates a copy of all of the items of the same type in the version. Subsequent changes to these items in the base application will not be reflected in the version. Changes to these items will only be reflected in versions of the base application if you have not made any changes to any items of the same type in the version.
NOTE A version may contain generated components (for example, functions and processes) that refer to dictionary items in the base application. Changes to the dictionary items in the base application will not be reflected in generated components in the version unless you generate the components again.
Unloading and Loading Versions Unloading and loading versions is a system administrator task. A version cannot be unloaded or loaded without the base application. Up to 10 versions can be unloaded or loaded with the base application. The HP ALLBASE/4GL Developer Administration Manual describes the procedures for unloading and loading applications and versions. Version Data File Reformat. HP ALLBASE/4GL provides a mechanism for automatically reformatting KSAM data files in the HP ALLBASE/4GL run-time environment. Data file reformatting may be necessary if you have changed the format of a record layout for a data file by changing the number of fields, changing the order of fields, or changing the details of fields. The HP ALLBASE/4GL run-time environment data file reformatting system relies on the structure file (xxxxS, where xxxx is the name of the data file) associated with each data file, and a file-structure file (in the group identified by the current value of the MPE/iX variable HP4FSPATH) created by the run-time application unloading procedure. During the subsequent application loading procedure, HP ALLBASE/4GL compares the existing file format, as described in the existing structure file with the new file format contained in the file-structure file. If the two formats are different, HP ALLBASE/4GL reformats the existing data files in the run-time environment. The automatic data file reformatting system cannot simultaneously reformat data file for both a base application and a version. To overcome this limitation, the run time file reformatting system only reformats the data files for the version if the version file format is different from the base application file format. To reformat data files for the base application only, the application must be unloaded by itself without any versions. This means that you may need to unload (and subsequently reload) an application twice if a version of the application uses data files with a different format. By initially unloading and then loading the application without the version, you can reformat the base application data files. By subsequently unloading, and then reloading the application with the version, you can reformat the data files for the version. Don't attempt to unload more than one version with an application if all the versions use different file formats. Refer to the HP ALLBASE/4GL Developer Administration Manual for more information about run-time data file reformatting.