My first Publication Agile-Data-Warehouse-Design-eBook | Page 45

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Chapter 1
Table 1-2
D ETAIL
Data Model Types
C ONCEPTUAL
D ATA M ODEL
L OGICAL
D ATA M ODEL
P HYSICAL
D ATA M ODEL
Entity Name
Relationship
Attribute Optional
Cardinality Optional
Primary Key
Foreign Key
Data Type
Optional
Table Name
Column Name
BEAM✲ and ER
notation are jointly
used to create
collaborative models
for different
audiences
DW/BI Audience Data Modelers
Business Analysts
Business Experts
Stakeholders
BI Users Data Modelers
ETL Developers
BI Developers Data Modelers
DBAs
DBMS
ETL Developers
BI Developers
BEAM ✲ Diagram Example Data
Table
Hierarchy Chart
Timeline
Event Matrix Conceptual
Diagrams
with Short Codes
Enhanced Star
Schema Enhanced Star
Schema
Event Matrix
Based on the detail levels described in Table 1-2 the order processing ERD in
Figure 1-10 is a logical data model as it shows primary keys, foreign keys and
cardinality, while the BEAM ✲ event in Figure 1-9 is a conceptual model (we prefer
“business model”) as this information is missing. With additional columns and
short codes it could be added to the BEAM ✲ table but each diagram type suits its
target audience as is. BEAM ✲ tables are more suitable for collaborative modeling
with stakeholders than traditional ERD based conceptual models. While other
BEAM ✲ diagram types and short codes compliment and enhance ERDs for col-
laborating with developers on logical/physical star schema design.
BEAM✲ Diagram Types
BEAM✲ also uses
event matrices,
timelines, hierarchy
charts and enhanced
star schemas
Example data tables are not the only BEAM ✲ modeling tools. BEAM ✲ modelers
also uses event matrices, hierarchy charts, timelines and enhanced star schemas to
collaborate on various aspects of the design at different levels of business and
technical detail. Table 1-3 summarizes the usage of each of the BEAM ✲ diagram
types, and lists their model types, audience and the chapter where they are de-
scribed in detail.
BEAM✲ supports the core agile values: “Individuals and interactions over proc-
esses and tools.”, “Working software over comprehensive documentation.” and
“Customer collaboration over contract negotiation.” BEAM✲ upholds these
values and the agile principle of “maximizing the amount of work not done” by
encouraging DW practitioners to work directly with stakeholders to produce
compilable data models rather than requirements documents, and working BI
prototypes of reports/dashboards rather than mockups.