Kevin Pheasey

Introduction Related Work How the language was implemented Main concepts of query language Test

Majority of the database querying systems developed for mobile access are for use on PDAs

The systems only provide minimal querying capabilities

Mostly pre-determined queries limits the use

Support for different types of queries as well as unplanned queries

Use Minimal Resources Be easy to use given the restricted screen

size

Current query languages are restricted by the domain of the application◦ Hung and Zhang telemedicine system◦ Kobayashi and Paungma transportation system

Systems cannot be put on a mobile phone because of a complex menu structure

Study shows users prefer direct input opposed to a menu system

Menus are acceptable on a PDA where a stylus is used◦ Polyviou, Samaras and Evripidou implemented a

directory like interface

Survey of 45 students

Created 3 queries each of a University database

Unplanned queries still conformed to the relational level of query expressiveness

A relation that contains all other relations (universal)

Different attributes must have different names and the same attribute must have the same name in every relation it‘s present

Useful in the normalization process Reduces terms in query formation

Lack of foreign keys Use of precise terms Minimal term ambiguity

Relation names denote all attributes will be displayed

Attribute name denotes the attribute will be displayed

Conditions only in a query denote that all attributes of the first relation tested will be displayed

STUDENT SUBJECT SUBJECT.name STAFF.name SUBJECT STAFF.name STAFF.ID=112971 SUBJECT.crhr>3

Prototype developed on Java phone emulator

Interface is drop down menus◦ interface for small

devices should be simple and use as many as possible high-level APIs

Created on Nokia 6681

Part 1◦ Pre-determined queries, allowed to ask for help

Part 2◦ Custom queries, allowed to ask for help

Part 3◦ Custom queries, no help, rated

Part 4◦ Pre-determined queries, no help, rated

Groups’ Overall Effectiveness Scores

Query Types’ Overall Effectiveness Scores

Group # Score

Group 1 96.5%

Group 2 97%

Group 3 99%

Relational Operation

Score

Projection 100%

Selection 95.4%

Join (w/ out condition)

99.2

Join (w/ condition)

98.1

Union/Set Difference

100%

Creating a free-form query language for mobile devices is possible

Free-form language eliminates the need for Join and simplifies the number of query inputs

Usability tests show the language is effective

?

Rohiza Ahmad, Sameem Abdul-Kareem, "A Free-Form Database Query Language for Mobile Phones," 2009 WRI International Conference on Communications and Mobile Computing, January 2009, 279-284.