Aug 11, 2010

Mobile Database Design



Design consideration and goals
Few aspects need to be considered in order to achieve the goals of designing the Mobile Database System or MDS. Performance need to be stabilized due to the mobility usage. The design of the MDS should be unobtrusive interface. The MDS is reliable to fulfill the high expectation of mobile users. Lastly the scalability of the MDS, these includes, everyone will synchronize at the same time. Merge replication, let database engines synchronize the local database that resides on the mobile device with a central database running on a server. Determine how the data will be imported or exported to the driving database on the server as part of the database strategy. Plan the synchronization strategy as part of the database design phase (Laberge R and Vujosevic S , 2002).
Mobile Database Design
Mobile database design is base on eight steps. The particular steps will help the design goal of MDS will succeed. The Figure 1 below will show the flow of the eight mobile database design steps.


1. Mobile Platform
Factors that may be considered when choosing a platform include, ease of use, ease of development, ease of communication, ease of deployment, product price, system reliability, product maintainability, communication bandwidth, technical support, and product popularity. It is also necessary to give considerations which kind of wireless communication techniques and network facilities are available to use with mobile applications. For example, which mobile operating system is the best for proper deployment of MDS? Current available mobile and laptop operating system include, Windows 2003/XP/Vista/7, Windows Mobile and PocketPC, Symbian OS 7.x/8.x/9.x, Linux, and Embedded Linux.

2. Mobile Database
Once the platform has been chosen, an appropriate mobile database management system will need to be selected. At this point, if it is determined that the mobile databases supported on the mobile platform selected earlier do not meet the requirements, and then it may be necessary to select another mobile database or to change to another mobile platform (Yu, W.D. and Sharma, 2007). For example IBM DB2 Everyplace and Oracle9i Lite (G Jim ,2008) . Oracle Database Lite provides a small footprint, SQL-enabled client database for local access to enterprise data by applications on the mobile device. In addition, it features the Mobile Server middleware component that supports scalable data synchronization and centralized management of mobile resources (Oracle.com)

3. Central Database
The selection of central database is parallel with mobile database selection, because the database needs to coexist in a single system while sharing the data. For example, if the SQL Server for Windows Mobile is used as a mobile database, SQL Server can be used as a central database to ensure interoperability, because both database management systems from the same vendor.

4. Transaction Model
An appropriate transaction model should be chosen depending on the model characteristics and user preferences. Names among transaction models are available in mobile environment Kangaroo, PRO-MOTION, Moflex, Cluster and Multi-Database.
5. Optimization Techniques
The compression technique provides the capability to move large amount of data between the mobile device and the central database server. The compression technique will make the best use of available bandwidth, the data transferred between mobile devices and the central database. This will not only improve the performance, but will also make the bandwidth available to the other users. Mobile devices have limited storage issues, the most frequent used data should be stored to make the best use of available space.

6. Database Entities
Identifying the database entities and the data is crucial. After the infrastructure related decisions have been made, decisions pertaining to storing the data need to be made.

7. Entity Attributes
While database entities are being identified, attributes contained in each of those entities will need to be considered. For each of those attributes, the data type and data size also need to be determined.

8. Entity Relationship Diagram
When the detail database entities and their attributes are finalized, an entity relationship diagram needs to be developed (Yu, W.D. and Sharma, 2007). This diagram will provide the relationships between different entities.
Database design process is the most critical part. This step involves making a number of important decisions and the above mention steps earlier plays vital roles in developing successful MDS

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