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Kevin Pheasey.  Introduction  Related Work  How the language was implemented  Main concepts of query language  Test.

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Presentation on theme: "Kevin Pheasey.  Introduction  Related Work  How the language was implemented  Main concepts of query language  Test."— Presentation transcript:

1 Kevin Pheasey

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

3  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

4  Support for different types of queries as well as unplanned queries  Use Minimal Resources  Be easy to use given the restricted screen size

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

6  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

7  Survey of 45 students  Created 3 queries each of a University database  Unplanned queries still conformed to the relational level of query expressiveness

8  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

9  Lack of foreign keys  Use of precise terms  Minimal term ambiguity

10  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

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

12  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

13  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

14 Groups’ Overall Effectiveness Scores Query Types’ Overall Effectiveness Scores Group #Score Group 196.5% Group 297% Group 399% Relational Operation Score Projection100% Selection95.4% Join (w/ out condition) 99.2 Join (w/ condition) 98.1 Union/Set Difference 100%

15  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

16 ?

17  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.


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