Abstract—It is a challenge to provide a wide range of queries to database query systems for small mobile devices, such as the PDAs and cell phones. Currently, due to the physical and resource limitations of these devices, most reported database querying systems developed for them are only offering a small set of pre-determined queries for users to possibly pose. The above can be resolved by allowing free-form queries to be entered on the devices. Hence, a query language that does not restrict the combination of query terms entered by users is proposed. This paper presents the free-form query language and the method used in translating free-form queries to their equivalent SQL statements. Keywords—Cell phone, database query language, free-form queries, unplanned queries. I. INTRODUCTION NABLING querying of information from remote databases anytime anywhere has become increasingly important for today’s highly mobile society. However, for developers to build a database querying system for small mobile devices that can support a large range of possible queries is rather a challenge. Since these devices such as the Personal Digital Assistants (PDAs), palmtops and cell phones are known to be limited in terms of their physical, resource and networking capabilities [1], majority of the database querying systems developed for them are solely dedicated to their intended applications. Hence, possible queries that can be formulated on these systems are mostly being pre-determined by the application developers as sets of options provided on a menu such as the systems presented in [2],[3] and [4]. However, such a measure tends to limit the usage of these systems. It leaves no room for users to issue other queries than those given. Furthermore, this approach of accepting only precise queries also hinders such systems from being easily adopted for other databases or applications. Therefore, a database querying system for mobile devices should be able to allow users to pose any query that they R. Ahmad is with the department of Computer and Information Sciences, Universiti Teknologi PETRONAS (UTP), Malaysia (phone: 605-3687477; fax: 605-3656180; e-mail: rohiza_ahmad@ petronas.com.my). S. Abdul-Kareem is attached to the Faculty of Computer Science and Information Technology, University of Malaya, Malaysia (e-mail: sameem@um.edu.my). want. And, this has to be done using as minimal resources as possible. Thus, in this paper, a query language which is free- formed will be introduced and explained. Using the language, users can combine any database schema term, i.e., relation name and/or attribute name, of their choice in any particular order to form queries. Hence, no pre-determined queries will need to be provided by the developers. The remainder of this paper is organized as follows. Section 2 highlights some related works, Section 3 introduces the free- form query language, Section 4 presents the translation process of converting free-form queries to relevant SQL statements, and Section 5 provides conclusions. II. RELATED WORK Database querying has been the focus of many database researchers for a long time. However, the capability of transacting queries while on the move using small mobile devices has only recently gained interest from the database community. Currently, the above interest is mainly targeted to mobile devices of considerable resources such as the PDAs and the palmtops. Even for these devices, the works reported are mostly application specific. For example, Hung and Zhang [2] presented a telemedicine system which can be used to access patient general information and medical conditions such as blood pressure (BP) reading and ECG diagramming on PDAs. Meanwhile, Koyama et al. [3] developed a system for education application. Their system can be accessed on PDAs by students who want to perform lesson’s unit test. Boonsrimuang, Kobayashi and Paungma [4], on the other hand, presented a system for transportation application, also on PDAs. Even though the above applications and others are undeniably important, they are very limited in terms of their functionalities. In other words, their usefulness is confined to a single domain of application, and even within that particular domain, they are restricted to the functions (queries) that have been pre-defined by their developers. Thus, there is no possibility for unplanned queries to be formulated on such systems. By using precise input query method as the above, unplanned queries are rather hard to implement since they require almost all combinations of possible query terms to be thought of beforehand by the developers. These terms will need to be presented on the system interface for the users to choose. Especially for mobile devices, this concept would be too expensive to implement due to the limitations mentioned earlier. Therefore, imprecise queries which freely combined any Free-Form Query for Cell Phones R. Ahmad, and S. Abdul-Kareem E