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11-11-2008_Mobile DB_DD

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

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11-11-2008_Mobile DB_DD

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  1. CS8630 Database Administration Dr. Mario Guimaraes 11-11-2008_Mobile DB_DD • Class • Will • Start • Momentarily…

  2. 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 • VIII) Point base • IX) Selecting a Mobile DB

  3. Mobile Databases: Functionality Required • communicate with centralized database server through modes such as wireless or Internet access; • replicate data on centralized database server and mobile device; • synchronize data on centralized database server and mobile device; • capture data from various sources such as Internet; • manage/analyze data on the mobile device; • create customized mobile applications.

  4. Mobile Databases : Why ? • Smart client applications have emerged as the architecture of choice over browser-based wireless Internet applications, as they enable access to data while the mobile user is disconnected from the network—wireless or otherwise. This capability is best implemented by incorporating persistent data storage using a mobile database in your application.

  5. Off-Line Access versus On-Line Wireless • The main advantage of using a mobile database in your application is offline access to data—in other words, the ability to read and update data without a network connection. This helps avoid problems such as dropped connections, low bandwidth, and high latency that are typical on wireless networks today. • More Adv. Of PDA

  6. Some facts are: 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.htm PDA: PALM or Pocket ?

  7. PDA: Palm or Pocket ? • Color, • Sound (MP3), • Superior for Games • Multitasking • Better Web Browser and Wireless Connectivity • the way the Pocket PC interacts, connects and seamlessly integrates within Microsoft-based servers and applications within IT environments • Microsoft partnership with hardware manufactures http://www.zdnet.com.au/newstech/communications/story/0,2000048620,20107806-1,00.htm

  8. PDA: Palm or Pocket ? • Round 1: Ease of usePALM • Round 2: Entering data Pocket • Round 3: Core applications Even • Round 4: Desktop compatibility PALM • Round 5: Email PALM • Round 6: Office compatibility Even • Round 7: Multimedia Pocket • Round 8: Available software PALM • http://www.zdnet.com.au/reviews/coolgear/pdas/0,39023392,39116317,00.htm

  9. Synchronization Questions • Will it be two ways (download & upload) ? • What happens if records have been added in both the consolidated database and the PDA since last synchronization ? • What happens if records have been modified in both the consolidated database and PDA since last synchronization ? • What happens if records have been deleted in one of the databases ? • What is the default action that my software performs ? • What can I do with the scripts ? • What type of transactional control exists in the synchronization (commit, rollback, etc.) ? • Will there be more than one PDA synchronizing with the Server at the same time ?

  10. Replication versus Synchronizing • "Replication" is about copying data. Typically one way process • Synchronization is typically a two-way process, however, where changes in the master copy are reflected in the local copy, and vice-versa. • Synchronization may involve data transformation.

  11. Hotsync (Palm) or ActiveSync (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 3) Backup/Restore 4) Network connectivity for docked PDA device 5) Data/File Synchronization (Synchronizes your e-mail, agenda, contacts, and other desktop programs).

  12. Limitations of Hotsync (Palm) or ActiveSync (Pocket) • Software is for synchronizing Database on PDA with Personal Database on Desktop or Laptop (not with Enterprise Database). • Only one synchronization link at a time.

  13. Database Front-End C, C++ Java Visual Studios (C++, VB, C#, J#) Appforge – (Mobile VB, Crossfire, bankrupt, Oracle) Database Backend Sybase’s Ultralite Sybase’s ASA Oracle Lite MS-Pocket Access MS-SQL Server CE Pointbase Mobile DB Environments

  14. iAnywhere (Sybase) • Market Leader (approx. 60% of mobile market) • Mobilink (Synchronization Server) • Ultralite (Mobile Database) or Adaptive Server Anywhere (ASA) • Can synchronize Data to Databases of different Vendors (not tied to Sybase’s Enterprise Edition). • Ultralite comes with Appforge’s Mobile VB http://www.ianywhere.com/events/ Free web-cast seminars

  15. Sybase’s Mobile Architecture

  16. Sybase - Ultralite Process SQL Statements  Reference Database  Database Schema | | | Application | (source) | | V V Ultralite Generator  Ultralite DB  Compiler (source) | V Application for PDA Note: Ultralite is not a trimmed down relational database engine.

  17. Advantages of Ultralite Process • Developers don’t have to learn 2 different DB • Only Included in Database Engine what is needed • Has power of the Server • Faster. Access Plans are already compiled • Obs.: Application can’t modify DDL (most applications don’t need to). • .usm: ultralite schema (created with ultralite schema painter) or other utility. • .udb: ultralite database (created by application program based on .usm) • For Ultralite User’s guide, click here

  18. Oracle Lite – Basics • Very Powerful • supports 100% Java development (through JDBC drivers and the database's native support for embedded SQLJ and Java stored procedures) • Supports programming from any development tool that supports ODBC (Visual Basic, C++, Delphi, and so on). • WindowsCE (Pocket) and PalmOS (Palm). • Includes Mobile SQL that is the mobile equivalent of Oracle's SQL*Plus tool. • Only Oracle DBMS significantly different.

  19. Oracle Lite – Some Differences between other Oracle Products

  20. Oracle Lite Architecture

  21. Oracle Lite – Sync • the Mobile Server product manages the synchronization of data to and from the mobile device (similar to Sybase’s Mobilink). • Unlike the Sybase, Oracle9i Lite assumes the use of Oracle databases on the Server. • Extremely Large Footprint (especially when using Web-to-go development tool or Wireless Bandwith).

  22. Web-To-Go • a component of Oracle9i Lite (wizard), consists of a collection of modules and services that facilitate development, deployment, and management of mobile Web applications. • Allows Oracle Lite users to perform replication, synchronization, and other networking issues without coding.

  23. Not Supported in Oracle Lite • PL/SQL (use Java Stored Procedures and triggers instead) • Oracle Lite is intended as a small, single-user client database and do not support any server functionalities like Java CORBA ORB's, SQL*Net Listeners, etc. • Only a few selected dictionary views are available, ALL_TABLES, ALL_VIEWS, ALL_USERS, CAT, etc. • An Oracle Lite database can only be queried from a remote client if it's data is replicated.

  24. Tutorials for Oracle Lite • http://www.oracle.com/technology/tech/wireless/tutorials/lite_windowscetutorial11-02.pdf • http://www.oracle.com/technology/products/lite/tutorials/index.html

  25. Pocket Access 2002 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

  26. SQL Server CE

  27. Pointbase • Like Oracle Lite, it is Java Based. • wide variety of platforms (more than Oracle Lite). • Its founder: Bruce Scott, cofounder of Oracle (with Larry Ellison).

  28. Choosing a Mobile DB • MS-Access Server ? -> Pocket Access • MS-SQL/Server ? -> MS-SQL/CE • Oracle Server ? -> Oracle Lite • Multiple Platforms -> iAnywhere (Sybase) • Multiple Platform, Java Development -> Pointbase • Oracle Lite: most powerful • Sybase’s Ultralite: small footprint, very flexible • XML, C & C++ ?

  29. DDB • DISTRIBUTED DATABASES

  30. For each employee, retrieve employee & dept. 3 Alternative solutions: 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.

  31. Query Decomposition • Must break up a query into subqueries that can be executed at the individual sites • Distributed and Replication Transparency: end-users and programmers must see the DB as if it was not distributed or replicated • At each site, there must be a list of distribution, fragmentation and replication.

  32. Create a Database Link • schema object in the local database to access a remote database. • remote db may be non-Oracle system (but you need to purchase a Oracle add on) • Example: CREATE DATABASE LINK sales.hq.acme.com CONNECT TO scott IDENTIFIED BY tiger USING 'sales'; SELECT * FROM emp@sales.hq.acme.com;

  33. Fragmentation Transparency(DD with Horizontal Partition) Create Salesview as Select * from sales@NY Union Select * from Sales@LA union Select * from Sales@Atlantadb; ------------------------------------------------- Select * from Salesview;

  34. Fragmentation Transparency(DD with Vertical Partition) 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;

  35. 2 Phase Commit 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. • 2 phase commit in oracle • Example in DB2

  36. Advantages of DDBMSs • Reflects organizational structure • Improved shareability and local autonomy • Improved availability • Improved reliability • Improved performance • Economics • Modular growth

  37. Disadvantages of DDBMSs • Complexity • Cost • Security • Integrity control more difficult • Lack of standards • Lack of experience • Database design more complex

  38. End of Lecture End Of Today’s Lecture.

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