1
  Brug af struktureret BI metadata - Common
Warehouse Metamodel (CWM)

• Torben Bach Pedersen
• Nykredit Center for Databaseforskning
• Aalborg Universitet
• www.cs.auc.dk/NDB

2
Indhold

• Struktureret versus ustruktureret metadata
• Motivation af fælles standard for DW metadata
• Common Warehouse Metamodel (CWM)
• Intro
• Layers
• XMI (meta data udveksling)
• API
• Fokus på muligheder fremfor detaljer
• 10 kms perspektiv
• Tak til Dan Chang og Doug Tolbert for lån af
  slides

3
Struktureret vs. ustruktureret

• Ustruktureret metadata ( dokumentation)
• Fordele
• Nemt at forstå og tilgå for mennesker
• Nemt at gå til og komme i gang med
• Ulemper
• Kan ikke læses af systemer gt metadata gemmes
  flere steder
• Ikke synkroniseret med systemer gt bliver ofte
  ikke vedligeholdt
• Struktureret metadata
• Fordele
• Kan læses af systemer gt metadata kan deles
• Kan synkroniseres med systemer gt bedre kvalitet
  over tid
• Ulemper
• Sværere at gå til og komme i gang med

4
Information Supply Chain (ISC)
Data Source
Data Mart
OLAP
Data Mining
Data Source
Operational Data Store
ETL
Data Warehouse
Data Mart
Reporting
Data Source
Data Mart
Visualization
5
Metadata Integration

• Metadata integration is a key prerequisite to
  ensuring the effectiveness of the data flow in an
  IFC.
• Achieving metadata integration between various
  software tools and products comprising an ISC is
  a difficult and costly undertaking.

6
Metadata Integration Using Bridges

• n(n-1)/2 udvekslinger (uden struktureret
  metadata skal det gøres i hånden)
• Samme argument for data ved DMs uden centralt DW

Operational Data Store
ETL
Data Warehouse
Data Mart
OLAP
ODS Metadata
ETL Metadata
DW Metadata
DM Metadata
OLAP Metadata
7
Metadata Integration Solution

• Solving the metadata integration problem requires
  the use of metadata standards that consist of
• Common metamodels
• Common interchange formats
• Common access APIs

8
Metadata Integration Using CWM Adapters

• Kun n udvekslinger
• Som for data med centralt DW

Operational Data Store
ETL
Data Warehouse
Data Mart
OLAP
ODS Metadata
ETL Metadata
DW Metadata
DM Metadata
OLAP Metadata
CWM (common metamodels, interchange formats, and
APIs)
9
CWM Enablement Showcase
10
CWM (Common Warehouse Metamodel)

• An OMG standard for metadata interchange in the
  data warehousing and business intelligence
  domain.
• Provides a common language (metamodel) for
  describing metadata.
• Provides an XML-based facility for interchanging
  metadata.
• Provides APIs for accessing metadata.
• Extends the OMGs metamodeling architecture to
  include data warehousing and business
  intelligence domain concepts.
• Supports the OMGs model-driven approach to
  software specification and system integration

11
OMG Metamodeling Architecture
Meta-level OMG terms Examples
M3 Meta-metamodel MOF Model (UML)
M2 Metamodel, meta-metadata UML Metamodel, CWM Metamodel
M1 Model, metadata UML models, Warehouse/BI metadata
M0 Object, data Modeled systems, Warehouse data
12
CWM facts

• CWM stiftet i
• IBM, Oracle, Unisys, Hyperion, Genesis, NCR,
• Initiel konkurrent Meta Data Coalition (MDC)
• BMC, Informatica, CA, NCR, Microsoft, SAS,
• Open Information Model (OIM)
• Fusionerer med CWM i september 2000
• Men hvor er MS nu??
• Version 1.0
• Februar 2001 (nyeste)
• De fleste store leverandører (vil i hvert fald
  gerne)
• 528 sider basisstandard
• 218 sider udvidelser (IMS, COBOL, Express,
  Essbase,)

13
CWM Layered Package Architecture
Warehouse Process
Warehouse Operation
Management
Transformation
OLAP
Data Mining
Information Visualization
Business Nomenclature
Analysis
XML
Record
Multi- Dimensional
Relational
Object (CoreBehavioral Relationships)
Resource
Business Information
Software Deployment
Data Types
Expressions
Keys Index
Type Mapping
Foundation
Core
Behavioral
Relationships
Instance
Object Model
14
Table, Column and View (Rltnl)
15
XMI Overview

• XML Metadata Interchange
• An XML vocabulary for
• interchanging metadata in software systems
• Specify a precise MOF to XML mapping
• Enables automatic generation of XML documents
  that can be validated with generated DTDs
• Allows interchange of any MOF based metamodel and
  corresponding models/metadata
• CWM metamodel
• CWM based metadata

16
XMI Example UML Model
CarModel.xml
Car
make
owner
owns
Person
model
ltClass name"
Car
"gt
ltClass.ownedElementsgt
drive()
ltAttribute name"
make
"/gt
ltAttribute name"
model
"/gt
ltOperation name"
drive
"/gt
lt/Class.ownedElementsgt
Convertible
lt/Classgt
17
API

• MOF to IDL Mapping
• The standard mechanism for accessing metadata in
  CORBA
• Access with C, C, COBOL, PL/1,
• MOF to Java Mapping (JMI)
• The standard mechanism for accessing metadata
  through Java

18
Resume

• Struktureret versus ustruktureret metadata
• Motivation af fælles standard for DW metadata
• Common Warehouse Metamodel (CWM)
• Intro
• Layers
• XMI (meta data udveksling)
• API
• Bruger nogen CWM nu ???
• Hvilken gavn kunne CWM være for jer ???