CS8630 Database Administration Dr. Mario Guimaraes 11-11-2008_Mobile DB_DD Class Will Start Momentarily… Introduction to Mobile Databases I) Mobile Databases: Basics II) PDA: Palm versus Pocket III) Synchronization IV) Mobile DB Alternatives V) Sybase VI) Oracle VII) Microsoft
Pocket PC multitasks (you can run several programs at once), Palm is intended to run one program at a time (although Palm OS 5.0 introduced some multitasking ability)
In 2001, there were over 13,000 commercially available software programs for Palm versus 1,600 for Pocket PC (although the gap is shrinking)
In 2001 Palm had a market share of 72% while Pocket PC had about 15%
Palms start at around $99 while Pocket PCs start around $200.
Some (sometimes faulty) user opinions/perceptions are:
Palm is easier to learn and use
Palm is more stable, Pocket PC crashes more
Pocket PC is more powerful
Pocket PC integrates better with Windows Office
Palm has more freeware and the software is cheaper
Palm is an Organizer, Pocket PC is a computer
http://palmtops.about.com/cs/pdafacts/a/Palm_Pocket_PC.htmPDA: PALM or Pocket ?
Program that comes free with PDA purchase. Run on the host (workstation, laptop) computer to permit it to exchange information with the PDA.
1) Connectivity for program installation
2) File browsing on PDA device
4) Network connectivity for docked PDA device
5) Data/File Synchronization (Synchronizes your e-mail, agenda, contacts, and other desktop programs).
Free web-cast seminars
SQL Statements Reference Database Database Schema
Ultralite Generator Ultralite DB Compiler
Note: Ultralite is not a trimmed down relational database engine.
applications don’t need to).
ADOCE database access classes.
for smaller database applications that need to operate on a small number of tables.
Pocket Access files are stored using the .cdb extension and are populated by one or more tables from a desktop Access database.
Replication/Synchronization is very simple, through ActiveSync
SQL Server 2000 Windows CE (SQL Server CE).
ADOCE database access classes or OLE DB/CE
replication with an enterprise SQL Server data store as well as advanced database capabilities.
Synchronized through RDA or Merge Replication (both through IIS)Microsoft’s Mobile Databases
1. Transfer both Employee and Department and perform join at Site 3.
2. Transfer the Employee to site 2, execute the join, send the result to Site 3
3. Transfer the Department to site 1, execute join, send both to site 3.
4. Use a semijoin operation. Project the columns needed before transferring.
CREATE DATABASE LINK sales.hq.acme.com CONNECT TO scott IDENTIFIED BY tiger USING 'sales';
SELECT * FROM email@example.com;
Create Salesview as
Select * from sales@NY
Select * from Sales@LA
Select * from Sales@Atlantadb;
Select * from Salesview;
SalesPart (pnum, cost, qty) at NY database
EngPart (pnum, materialType, supplier) at LA database
Create View Part as
Select pnum, cost, qty, materialType, supplier
From SalesPart@NY sp, EngPart@LA ep
Where sp.pnum = ep.pnum;
Select * from Part;
Phase 1: prepare to commit. Each participant writes log buffer to disk and reply to coordinator (DB that establishes link)
Phase 2: if all databases reply OK, the coordinator
will send a commit to all. Otherwise, everything
is rolled back.