2
Concepts

2.1.1 Mobile Client

The Mobile Client tier consists of the Oracle Lite database, Mobile Sync, and a client machine or a handheld device running one of the following compatible operating systems:

• Windows NT 4.0 SP6a, Windows 2000, or Windows 95/98

• Palm OS

• Windows CE/Pocket PC

• EPOC

You can install the Mobile Client for Web-to-Go only on a machine running a Windows 32 operating system.

The Mobile Client for Web-to-Go consists of the Mobile Client Web Server and the Oracle Lite database.

The Mobile Client for Web-to-Go can be accessed from a browser on Microsoft Windows. The browser should be either Netscape 4.5 or higher, or Internet Explorer 5.0 or higher. If you use Internet Explorer, it is recommended that you use Internet Explorer 5.5 and the Internet Explorer 5.5 Service Pack 2. Users and administrators should enable Web cookies in their browsers.

2.1.2 Mobile Server

The application server tier contains the Mobile Server, which processes requests from the Mobile Client to replicate data in the database server. The Mobile Server is a module that operates with the Oracle9i Application Server (Oracle9iAS). The Mobile Server runs as a component of Oracle9iAS.

The Mobile Server also runs in the standalone mode.

2.1.3 Database Server

The database server tier stores the application data and the application and system files. The files are stored in the Mobile Server Repository, a virtual file system that resides on Oracle. It is a persistent resource repository that contains all application files and definitions of the applications.

An application is available to the user after the administrator publishes it to the system and grants access privileges to the user.

2.2.1 Data Synchronization

During data synchronization, the Mobile Client uploads data changes into the in queues in the Oracle database. The client then downloads the new changes from the out queues and applies these changes to the local Oracle Lite database.

The Consolidator Message Generator and Processor (MGP) is a Java background process that applies the pending transactions from the queues to the Oracle database at set intervals. It also generates new data changes for the Mobile Client to download. These changes are stored in out queues from where the Mobile Client retrieves them the next time it synchronizes. Data changes uploaded by the Mobile Client are not reflected in the Oracle database tables until the MGP has processed the in queue and applied those changes. Similarly, any changes made to the Oracle database tables after the MGP has run are not added to the out queue and are not downloaded when the Mobile Client synchronizes.

As Figure 2-2 illustrates the synchronization process, you can use the Mobile Client to upload changes into the in queue and download updates in your out queue even if the MGP is not running. However, your in queue will not be processed, and your out queue will not receive any new changes.

You can start and stop MGP from within the Mobile Server Control Center.

2.2.2 Synchronizing the Data and Application

When the user synchronizes, the Mobile Server replicates the data changes that the user made locally to the Oracle database. The data changes that the user made to the data in the Oracle database are applied to the data in the Oracle Lite database on the the Mobile Client.

In addition, any application changes are downloaded to the Mobile Client.

In Web-to-Go, data and applications are also synchronized when the user switches from the online mode to the offline mode or from the offline mode to the online mode.

2.3.1 The Mobile Server Control Center

The Administrator uses the Mobile Server Control Center to install the application in the production system. After publishing the application, the Administrator can use the Mobile Server Control Center to assign application access privileges to users.

Using the Mobile Server Control Center, the Administrator can create and modify access control on an application by granting or revoking access to individual users or groups. The Administrator can also use the Mobile Server Control Center to perform other administration tasks, such as:

• Create users and groups.

• View server status.

• Start, stop, and review status of MGP, which is the asynchronous replication engine.

• View site information.

In addition, the Administrator can use the Mobile Server Control Center to change an application's properties by doing the following:

• Modify the number of connections that an application manages in its Web-to-Go connection pool.

• Change the Oracle database login user name and password.

• Determine which subset of the data is downloaded to the client.

2.3.2 Web-to-Go Roles

A Web-to-Go role is a privilege level which is specified within the application only in Web-to-Go. The developer creates roles in the application's code. It is an attribute of the user and of the application.

For example:

role=employee

For information on using the Packaging Wizard to define application roles, see Oracle9i Lite Developer's Guide for Web-to-Go.

After the Administrator publishes the Web-to-Go application to the Mobile Server, the Administrator can assign roles to users and groups by using the Mobile Server Control Center. The Administrator determines a user's application access by assigning roles to users and groups. For example, the server has three different applications (Applications A, B, and C) and two users (Jane and John) who both have varying roles. Jane has the role of employee and developer for two different applications. John has the role of manager and employee for two different applications.