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XCube XML for Data Warehouses Wolfgang Hmmer Andreas Bauer Gunnar - PowerPoint PPT Presentation

Nov 25, 2022 •591 likes •826 views

XCube XML for Data Warehouses Wolfgang Hmmer Andreas Bauer Gunnar Harde DOLAP 2003 New Orleans Motivation/Outline DOLAP 2002 XML standard for Data Warehouse data is desirable Possible benefits Integration/federation of

  1. XCube XML for Data Warehouses Wolfgang Hümmer Andreas Bauer – Gunnar Harde DOLAP 2003 New Orleans

  2. Motivation/Outline � DOLAP 2002 � XML standard for Data Warehouse data is desirable � Possible benefits � Integration/federation of Data Warehouses � Standardize MD data model � Data Warehouse Web Service Motivation 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  3. The Download Use Case � Web Cube � Data Warehouse cube formulated in XML � Web server offers Web Cubes download schema download dimensions download facts Local Web Web Network DW server cubes Motivation 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  4. The Query Use Case � Download case plus selective query � Benefit: reduce network traffic download schema download dimensions query download selected facts Local Web Web Network DW server cubes Motivation 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  5. Further Use Cases � The Generating Use Case � Create Web Cubes from raw data � Create Web Cubes from existing Data Warehouse data � Introduction of Standard Dimensions � Federation of Data Warehouses � Data Warehouse Portal � … Motivation 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  6. Requirements for Web Cubes � Support for multidimensional model(s) � Distinction between � Multidimensional schema � Dimension/master data � Facts/transaction data � Flexible: reuse and extensibility � Suitable for transport over networks Motivation 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  7. XCube � Collection of XML formats for � Describing MD data cubes, i.e. Web Cubes � Formulating simple queries on data cubes � Goal: exchange of warehouse data � Note: XCube is not a (proper) query language! � Joint development of OFFIS and FAU Basic formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  8. Overview – XCube Formats � Basic XCube Formats � XCubeSchema � XCubeDimension � XCubeFact � Advanced XCube Formats � XCubeText � XCubeQuery � XCubeFunction Basic formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  9. XCubeSchema � Description of MD structure � Contains links to � Dimensions & their hierarchy levels � Facts � Extensions � Multicubes � Data types & unit types � Computed facts � Inheritance, composition � Standard Time Dimension � … Basic formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  10. XCubeSchema – Example < multidimensionalSchema …> < cubeSchema id= " sale "> < multidimensionalSchema> < fact id= " sales "/> < fact id= " revenue "/> < dimension id= " geography " granularity= " branch "/> < cubeSchema> < dimension id= " product " granularity= " article "/> < /cubeSchema> * < fact> < classSchema> geography * < classLevel id= " branch "> < dimension> < attribute id= " manager "/> < rollUp toLevel= " city "/> < classSchema> < /classLevel> < classLevel id= " city "> * < rollUp toLevel= " region "/> < classLevel> < /classLevel> product * < classLevel id= " articl e"> < rollUp> < attribute id= " articleName "/> < attribute id= " brand "/> * < attribute> < rollUp toLevel= " productGroup "/> < /classLevel> < classLevel id= " productGroup "> < rollUp toLevel= " productFamily "/> < /classLevel> < /classSchema> < /multidimensionalSchema> Basic formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  11. XCubeDimension � Store data of single dimension � Populate classification levels from above � Assign units to nodes � Special features � Shared Roll-Ups � Versioning of nodes � Reuse & refine standard Time-Dimension Basic formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  12. XCubeDimension – Example < dimensionData version= "0.4“ …> < units> < entry unitType= " currency " unit= " EUR "/> < /units> < classification> geography < dimensionData> < level id= " country "> < node id= " Germany "/> < node id= " Switzerland "/> < units> < node id= " France "/> < /level> * < entry> < level id= " region "> < node id= " Northern Germany "> < classification> < rollUp toNode= " Germany " level= " country "/> < /node> * < node id= " Western Germany "> < level> < rollUp toNode= " Germany " level= " country "/> < /node> * < node> < node id= " Eastern Germany "> < rollUp toNode= " Germany " level= " country "/> * < /node> < attribute> < node id= " Southern Germnamy "> < rollUp toNode= " Germany " level= " country "/> * < rollUp> < /node> < /level> < /classification> < /dimensionData> Basic formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  13. XCubeFact � Stores facts of a data warehouse cube < cubeFacts version= "0.4“ …> < cube id= " sale "> MD coordinates < cell> < dimension id= " geography " node= " branch48 "/> < cubeFacts> < dimension id= " product " node= " MA-450 "/> < dimension id= " time " node= "2003-07-24"/> * < cube> < fact id= " sales " value= "3"/> * < fact id= " revenue " value= "960"/> < cell> < /cell> fact values * < dimension> < cell> < dimension id= " geography “ node= " branch75 "/> * < fact> < dimension id= " product " node= " MA-450 "/> < dimension id= " time " node= "2003-07-24"/> < fact id= " sales " value= "2"/> < fact id= " revenue " value= "640"/> < /cell> < /cube> < /cubeFacts> Basic formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  14. Short Summary � What we have so far � XCubeSchema � XCubeDimension � XCubeFact � Result � We are able to express a complete data cube in XML Basic formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  15. XCubeQuery � Dynamically explore a web cube � Not meant to be YAQL � Reduce network traffic by drilling down to the area of interest � Usability depends on ability of the data source � E.g. “dumb” sources cannot slice & dice � Problem treated with XCubeFunction Adv. formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  16. XCubeQuery – Sequence (1) Get List of Cubes < getCubeSchema> < cubeSchema> * Get facts & dimensions < getCubeSchema id= …> < cubeSchema id= …> < fact> * < dimension> * Client Server Adv. formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  17. XCubeQuery – Sequence (2) Get all information on dimension(s) < getClassSchema> < dimension id= …> * < class Schema> < classLevel id= …> * < dataTypes> < dataType name= …> * < unitTypes> < unitType> * Client Server Adv. formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  18. XCubeQuery – Sequence (3) Get facts < getFacts> < cube id= …> * < dimension id= …> * < fact> * < cube id= …> < cell> * < dimension id= … node= …> * < fact id= … value= …> * Client Server Adv. formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  19. Further XCube-Standards � XCubeFunction � Query the abilities of a server holding web cubes � Determines to what degree XCubeQuery can be used � XCubeText � Add textual descriptions/comments � In place vs. external file(s) Adv. formats 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

  20. Prototypical Implementation � XCube-Generator � Windows 2000 Oldenburg � MS SQL Server & TPC-H data OLAP Services � XCube-Loader � Solaris 8.0 � Oracle 9i Erlangen � TPC-H data � Scale Factor 1 Prototype 12.11.2003 W. Hümmer - XCube Motivation Basic formats Adv. formats Prototype Summary

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