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Data Modeling on Steroids: Patterns and Reusability
Presented by Bert Scalzo, [email protected]
About the AuthorAbout the Author
Oracle DBA for 18+ years, versions 4 through 10g Worked for Oracle Education & Consulting Holds several Oracle Masters (DBA & CASE) BS, MS, PhD in Computer Science and also an MBA LOMA insurance industry designations: FLMI and ACS Books
– The TOAD Handbook (March 2003)– Oracle DBA Guide to Data Warehousing and Star Schemas (June 2003)– TOAD Pocket Reference 2nd Edition (June 2005)
Articles– Oracle Magazine– Oracle Technology Network (OTN)– Oracle Informant– PC Week (now E-Magazine)– Linux Journal– www.Linux.com
About Quest Software
We provide application management solutions that enable customers to:
•Develop•Deploy•Manage•Maintain
enterprise applications without downtime
What is Application Management?A holistic approach of managing the entireapplication - not individual components
How Do We Do It?We surround the application infrastructure:
High Availability
Database Management Microsoft Infrastructure Management
Application Monitoring
Agenda Definition of Pattern Benefits of Designing for Reusability Super and Sub Type Pattern Intersection Patterns
– Many to many relationships– Roles– Assemblies
World of Modeling …
• Identify all data & relationships - E/R (Entity/Rel’ship) diagrams - DB independent view• Business Rules?
Conceptual Data Modeling(CDM – E/R)
Physical Data Modeling(PDM)
Business Process Modeling(BPM)
Object-Oriented Modeling(OOM - UML)
• DB-specific model• Reverse engineer existing DB• Create/Update DB from model• Data Warehouse Modeling
• DBA• DB Developer• DB Architect
• Bus. Analyst • Data Architect• Data Analyst
• System Architect• System Analyst• App Developer
• End-user• IT Partner/Liaison• Business Analyst
• Support for all UML diagrams - Analyze requirements - Design application• Reverse/forward engineer code
• Improve process efficiency• Define/document Bus. Processes - create correct and complete application requirements
QDesigner synchronizes models from all levels in a single tool
Basic Premises of Design Patterns Not everything is specialized
Simply reuse what’s reusable
Anyone can do this (really…)
Not that hard to do technically
Merely requires some up front work
Not Everything is Custom How many of your businesses are so
specialized that you require custom modeling of everything?
We all have:– Customers– Products– Contracts– Orders– Addresses– etc, etc, etc …
These base concepts are often repeated within one company across projects, departments, divisions …
Side Effects of Customization I had one insurance company for:
– Life and Accident– Automobile– Home Owners– Health Insurance– Administer 401K– Variable Annuity
I later worked for that company– Nearly 1000 entities– Close to 20,000 attributes– In a year, we simplified the model by 90%!!!
Each statement was mailed using a different address style (i.e. diff info) , and it took 6 separate change of address cards when I moved. So I switched insurance companies
Benefits of Re-Usable Models
Takes time, but often yields: Better data models
– More robust fundamental business knowledge
Better database design– More accurate implementation of business requirements
Less rework– Avoids last minute implementation/coding discoveries
Less end-user re-training– Systems won’t need to be reworked and redeployed
Centralized databases– All can be based upon common modeling best practices
Anyone Can Re-Use ModelsRegardless of “IS” shop organization Centralized Modeling group – easy Centralized Data Admin – again, easy Departmental or Project Oriented:
– Merely requires open communication – Helps to all use the same modeling tool– Helps for everyone to follow some fundamental
modeling rules, guidelines and best practices– Can still work in a limited fashion with none of the
above – through grass roots efforts to work smarter
Consultants – simply require all data models be part of walk-throughs and deliverables (help them learn the business)
Simple Pattern: 2 Constructs Simply requires the appropriate, consistent
and liberal use of just two very basic data modeling constructs
1. Super and Sub Types
2. Bridging/Intersection Entities– NOTE: There are two highly specialized intersection
scenarios for making reusable modeling components• Roles• Assemblies (sometimes called B.O.M. solution)
Super and Sub Types In the business world, we often find that things (i.e.
entities) do not fall into simple, clear cut classifications– We sometimes find that things are very similar - with just a few
differences
In data modeling, this can be referred to as:– Entity Inheritance– Super and Sub Types– Generalization Hierarchies
The key question to ask is whether these different classifications are:– Exclusive: must be one way or the other– Inclusive: can actually be all ways at once
http://www.quest.com/whitepapers/Reality_Requires-QDesigner.pdf
Candidate for Super/Sub
Very similar entities in concept - some common attributes, but also some differing attributes …
Super/Sub Type Pattern
X means Exclusive
Super/Sub Meta-Data
This Super/Sub Type Meta-Data is only important for transforming conceptual to physical model…
Intersection Patterns There are three ways to use intersections:
1. Resolve basic many-to-many relationships• Not very intrinsically useful, but must mention
for clarity
2. As “Roles”• Powerful concept• Can greatly reduce data model size
3. As “Assemblies”• Powerful concept• Can enable flexible database design
Resolve Many-To-Many
You CANNOT physically implement the concept of many-to- many relationships in a relational database
You may potentially miss multiple key business requirements Many modeling tools will attempt to automatically resolve this
Intersection Meta-Data
Candidate for RolesUnlike Super/Sub types, we now have identical or near identical entities coming together into an intersection …
Poor Choice for Roles
Often, a first attempt to resolve the “Role” concept uses relationships. But there are two problems with this approach:1. What if “Role” participation requires additional attributes?
Where would you place them?2. What if business requirements change and you need to
add or subtract “Role” participants? How do you later add and subtract foreign keys in databases?
Solution for RolesBy creating a “Role Type” as entity rather than attribute, adding/dropping Roles doesn’t require database change!
Candidate for Assemblies
Solution for AssembliesThis does everything the prior model does, with the advantage of not being fixed in terms of what things can be combined or in levels of hierarchical combinations possible …
PartsMinor ComponentsMajor ComponentsProducts
Assemblies Good for Anything At insurance company, we used Assemblies to build
dynamic product offerings comprised of:– Features– Federal Rules– State Rules– etc, etc, etc …
Real Benefit: new products required no new application systems, just a few new rows of data in existing tables
Product time to market reduced by 50%!!!
Assemblies Work …
1 Part 1 Screw 1 5 1
2 Minor 2 Nut 1 5 2
3 Major 3 Washer 1 5 3
4 Product 4 Bracket 1 6 1
5 Widget 2 6 4
6 Gadget 2 7 5
7 Sprocket 3 7 6
8 Cog 3 8 1
9 Gizmo 4 8 5
9 7
9 8
ComponentType
Component Assembly
How many base parts in a Gizmo? (nine)
Did You Notice …???Roles and Assemblies are nearly the same thing …
Parting Thoughts Many Design problems have already been solved Data Model constructs can be re-used as easily as code
– Carefully consider which business requirements are really unique– Must look for ways to reduce model complexity while making it “generic”
There are many other modeling issues – this was just a start …– Breaking models into sub-models– Round-trip Engineering:
• Conceptual -> Physical Model compare and sync• Physical Model -> Database compare and sync
– Repository-based collaborative modeling– Horizontal and Vertical Partitioning– Data Warehousing (Star Schema design)– Object-Relational Mapping– etc, etc, etc …
More Information Free 45-Day Trial of QDesigner™
– http://www.quest.com/QDesigner– Compete enterprise modeling solution
• Business Process Modeling (BPM)• Object-Oriented (UML) Modeling (OOM)• Conceptual Data Modeling (CDM)• Physical Data Modeling (PDM)
Save $$$: Upgrade your TOAD/SQL Nav license to the Suite– Suites include PDM!!!
Modeling White Papers– http://www.quest.com/whitepapers/qdesigner/index.asp
• Data Modeling: Common Mistakes and Their Impact• Data Modeling: It's Really All About the Relationships• Data Modeling: Reality Requires Super and Sub Types
QUESTIONS & ANSWERS