Database support on smartphones is migrating towards systems traditionally the domain of enterprise servers. Symbian Ltd. has already taken a step in this direction, with the implementation of SQLite in Symbian OS v9.5. However, third party solutions are taking smartphone databases even closer to the enterprise.

Mimer Information Technology has supported Symbian OS in Mimer SQL Mobile for a number of years. Now support for S60 3rd Edition and UIQ 3 is being provided in the forthcoming Mimer SQL Mobile v9.3. "Symbian is an important and interesting platform for us," says Stefan. "Until recently we have been seeing a greater demand for our technology on other platforms. Now, Symbian applications seem to be going through a transition and data management is becoming more important."

This change is being driven by the increasing acceptance of Symbian smartphones in the enterprise. "Enterprises are changing their attitude towards smartphones," says Stefan. "Smartphones and even some mid-range devices are becoming capable of processing large amounts of data. As this happens, we are seeing enterprises looking at smartphones as application platforms. This is starting to drive an increasing demand for proper database management systems on these devices."

With Mimer SQL Mobile Stefan claims that developers have access to a very large subset of the features they are familiar with from enterprise grade SQL databases. This includes features such as: procedures, triggers, Unicode, multilingual collation support, binary large objects support, fine grained security, and transactions, among others.

Despite this feature coverage, the full version of Mimer SQL Mobile is delivered to Symbian devices in an application of 800 kB. However, even with the increasing storage capacity on smartphones, this makes Mimer SQL Mobile a relatively large application. To address this, developers can choose to install a smaller version, for example by limiting applications to using static SQL statements, rather than building them on-the-fly. In addition, by working with Mimer, the database executable size can be reduced further with custom tailoring.

To create a Mimer SQL Mobile database for a Symbian device, the database is defined on a PC using Mimer's free development tools. All application development can be undertaken on the PC, in the same way as other Symbian applications are developed. Once the application has been tested the database can be packaged and installed on a device. Once on the device the database structure remains static, however v9.3 includes features to automatically upgrade the device's database when a new version is copied over.

"We see the database as a standard software architecture component," says Stefan -Mimer is an active member of the ISO SQL committee. "As a result, we focus on providing open APIs for Mimer. In the case of Mimer SQL Mobile for Symbian, this means a Java and Symbian C++ interface."

Mimer SQL Mobile for Symbian is implemented as a standard Symbian server component. This allows several applications to access data simultaneously. In addition, Mimer SQL Mobile can serve data to applications running on remote devices. A remote device connected through the mobile network, over WiFi, or even Bluetooth can (when it has suitable security credentials) query a database. Quite why this might be useful may not be self evident. There are however at least two practical uses to this technology.

"Today, users synchronize PC email and calendars with their smartphones," says Stefan. "As we see people carrying their smartphones all the time and storing more data on them, the smartphone is becoming the primary data repository. Therefore, it will soon be the PC that synchronizes with the smartphone to keep the PC up to date, not the other way round. As this paradigm change happens the smartphone needs to act as a database server and this is exactly what Mimer SQL Mobile enables."

While the smartphone centric world may be a few years away, a more present application of a database server on a smartphone is for data synchronization. With the smartphone database acting as a server it offers flexibility in the way middleware can synchronize mobile data with remote databases.

However, Stefan points out that custom middleware components are not needed to synchronize a Mimer SQL database. From v9.3 Mimer's products include synchronization and replication features for mobile. "We also support open standards," says Stefan. "This means developers can use a number of third-party solutions for synchronization."

While smartphones are becoming more powerful, they still lag behind the processing power and memory available on servers and PCs. Does this mean that the extra functionality of a full database means slow performance on a smartphone? Not according to Stefan. "We have benchmarked Miner SQL Mobile against the Symbian database, Mimer is faster by a factor of two to ten," says Stefan. "Simple selects and deletes show the smallest performance advantage. However, with a table join we are seeing ten time performance improvements using Mimer compared to doing the join in code, as you have to with the Symbian database. We believe if we benchmarked using features such as procedures, we would see even more significant performance improvements."

To get these improvements into the hands of mobile application developers Stefan notes that Mimer has a very flexible approach to licensing. "We don't want a software vendor to have to create a new business model to use Mimer in their development," says Stefan. "So we try to work with a developers existing software licensing model. Even when working with more traditional ISVs and VARs we realize that one size does not fit all. So whether the developer charges a one time fee for their software or rents it using a subscription model, we believe we can find a suitable licensing model. Equally, high volume applications are typically low priced and vice-versa; again we can work with both models."

Given Symbian OS delivers a database to developers for free and will be adding support for SQLite in Symbian OS v9.5, how does Stefan see the market growing?

"At the moment we see a lot of homegrown data management solutions in mobile applications," says Stefan. "However, we expect that to change as mobile applications start to encounter the same problems that triggered the creation of relational databases in the first place. Mimer SQL Mobile not only solves the data management problem, but can help address some of the challenges facing mobile developers. For example, Unicode collation support makes it much easier for developers to deliver applications that sort in the right order for different languages, which is difficult to code themselves."

Another placre where Unicode collation helps developers is in performing searches appropriately for a specific language, for example:

SQL>select * from t where name like 'AA%' collate danish_1;

Results in:

NAME
====
Aalborg
Århus
etc.

Even so Stefan believes it will be a while before there is a significant demand for high-volume database intensive applications on Symbian devices.

"From our point of view delivering a fully functional database to mobile devices makes sense and not just for enterprise applications" says Stefan. "Smartphones are no longer dealing with a handful of contacts, but hundreds; not just a few megabytes of pictures or music, but gigabytes. To manage this scale of data developers need the functionality delivered with Mimer SQL Mobile."

For more information on Mimer SQL Mobile visit www.mimer.se

Mimer SQL Mobile is also available for Windows Mobile, Linux, and a number of features phones.