Sure, data modeling is taught in many training classes as a linear process for building software. It usually goes something like this:
- Build a Conceptual Data Model.
- Review that with users
- Build a Logical Data Model
- Review that with users
- Build a Physical Data Model
- Give it to the DBA
- GOTO step one on another project.
And most team members think it looks like this:
Training classes work this way because it’s a good way to learn notations, tools and methods. But that’s not how data modeling works when the professionals do it on a real project.
Data modeling is an iterative effort. Those integrations can be sprints (typical for my projects) or have longer intervals. Sometimes the iterations exist just between efforts to complete the data models, prior to generating a database. But it’s highly iterative, just like the software development part of the project.
In reality, data modeling looks more like this:
This is Data Model-Driven Development. The high-level steps work like:
- Discuss requirements.
- Develop data models (all of them, some of them, one of them).
- Generate Databases, XML schemas, file structures, whatever you might want to physically build. Or nothing physical, if that’s not what the team is ready for.
These, again, are small intervals, not the waterfall steps of an entire project. In fact, I might do this several times even in the same sprint. Not all modeling efforts lead to databases or physical implementations. That’s okay. We still follow an iterative approach. And while the steps here look like the same waterfall list, they aren’t the same.
- There isn’t really a first step. For instance, I could start with an in-production database and move around the circle from there.
- We could start with existing data models. In fact, that’s the ideal starting point in a well-managed data model-driven development shop.
- The data models add value because they are kept in sync with what’s happening elsewhere – as a natural part of the process, not as a separate deliverable.
- The modeling doesn’t stop. We don’t do a logical model, then derive a physical model, throwing away the logical model.
- Data modelers are involved in the the project throughout its lifecycle, not just some arbitrary phase.
- Modeling responsibilities may be shared among more roles. In a strong data model-driven process, it is easier for DBAs and BAs to be hands-on with the data models. Sometimes even users. Really.
By the way, this iterative modeling approach isn’t unique to data models. All the models we might work on for a project should follow this project. Class diagrams, sequence diagrams, use cases, flow charts, etc. should all follow this process to deliver the value that has been invested in them. That’s what Agile means in “the right amount of [modeling] documentation”. Data model driven development means that models are “alive”.
If you are a modeler and re-enforcing the wrong perceptions of needing a waterfall-like approach to data modeling, you are doing it wrong. You might be causing more pain for yourself than anyone else on your project.
Data Models aren’t just documentation checklist items. They model the reality of the living, breathing systems at all points in its life. They deliver value because they are accurate, not because they are “done”.
This Thursday, 20 September 2012, I’ll be joining a great group of data professionals to talk about balancing the need for project speed with data modeling efforts. This is a topic near an dear to heart — I’m developing courseware right now for advanced data modeling concepts on modern development efforts. DM Radio, hosted by Eric Kavanagh and Jim Ericson, is always a fun and thoughtful take on modern IT practices. Plus a few of us are known for our snarkish insights into the data world.
The value of data modeling continues to grow in new directions. This is partly due to the lure of cloud computing, but also because of the increasingly interconnected world of enterprise partnerships. As always, the need for speed and efficiency prevails, as well as the desire to reduce redundancy and thus provide a clean view of an organization’s information architecture. Fine-tuning Master Data Models is another goal of the modern enterprise. What to do? Register for this episode of DM Radio to hear Hosts Eric Kavanagh and Jim Ericson interview data modeling expert Karen Lopez of DAMA, plus Donna Burbank of CA Technologies, David Dichmann of SAP Sybase and Lovan Chetty of Kalido
Registration is required, but it’s free. Chat with you on Thursday!
On Thursday, 2 August I’ll be debating with Tom LaRock (@sqlrockstar), giving a preview of our SQL Saturday presentation of Database Design Throwdown: The Trailer. In this wonderful smackdown, I’ll be talking about the importance of data quality, integrity and data governance while preparing database designs. I’m pretty sure Tom will be spouting wildly crazy, kooky ideas about performance, optimizing design to make life easier for DBAs and … I have no idea what else. Probably bacon. We won’t be giving the same presentation as on Saturday — it will be more of a trailer version of that. Oh, wait…that doesn’t quite sound right. It will be a teaser. Yeah. Something like that. A teaser.
Kansas City SQL Server User Group
Details about the SQL Server User Group meeting:
- 3:45 – 3:50 Greeting and Housekeeping
- 3:50 – 5:00 Database Design Throwdown: The Trailer
- 5:00 – 5:15 Door prizes and wrap up
Overview: If a man is alone in the forest and there is no woman around to watch him design a database is he still wrong? Join us in this highly interactive debate regarding the options and best practices of common and advanced design issues such as natural versus surrogate keys, NULL versus NOT NULL, data quality versus performance, and others. Bring your opinions and experience and join the discussion.
Thomas LaRock is a seasoned IT professional with over a decade of technical and management experience. Currently serving as a senior database administrator with Confio Software, Thomas has progressed through several roles including programmer, analyst, and DBA. Prior to that, he worked at several software and consulting companies, working at customer sites in the United States and abroad. Thomas holds a MS degree in Mathematics from Washington State University and is a member of the Usability Professional’s Association. Thomas also currently serves on the Board of Directors for the Professional Association for SQL Server (PASS), is a SQL Server MVP, and can also be found blogging at http://thomaslarock.com and is the author of DBA Survivor: Become a Rock Star DBA (http://dbasurvivor.com).
Karen Lopez is Sr. Project Manager and Architect at InfoAdvisors, Inc. Karen is a frequent speaker at conferences and user groups. She has 20+ years of experience in project and data management on large, multi-project programs. Karen specializes in the practical application of data management principles. Karen is also the ListMistress and moderator of the InfoAdvisors Discussion Groups at www.infoadvisors.com.
8700 State Line Road
Leawood, KS 66206 (map)
Data Model Driven Database Design
On Saturday, 4 August I will be presenting at the Kansas City SQL Saturday (aka #SQLSat159 — don’t get me started on why they use a surrogate key as their names for these…) on Model Driven Database Design
Model-Driven Database Design
Model-Driven Database Development: Myths, Magic and Methods. In this presentation, Karen discusses data model-driven database development from the point of view of the Data Architect, the DBA, and the Developer. She will cover topics such as "Who does what?", "Why are we doing this?", "Do I have to Use a GUI?" and "Just who do you think you are?". Demos, too. Finally, 10 tips for making model-driven database development successful in your organization’s culture and environment.
Session Level: Beginner
Location: Cerner Corporation’s Riverport Campus, 6711 NE Birmingham Rd, Kansas City, MO, 64117
And Tom and I will be doing our full debate on Database Design: The Throwdown, as described above. Registration is required for the SQL Saturday, but it’s totally free – you get swag, prizes and access to some of the best speakers in the SQL Server community. I attended this last year in Kansas City and they did a fabulous job. You want to be there, too.
I’ll be presenting Model Driven Database Design on Saturday, 5 November at the SQL Saturday Washington DC. Which is being held in Chevy Chase, Maryland. Yes, I know this is the greater DC area. Last year it was held in Reston, Virginia. But these data things drive data architects crazy. That’s why you really don’t want to live with a data architect. Ever.
Anyway, I’ll be presenting a brand new presentation that covers:
Model-Driven Database Design
Model-Driven Database Development: Myths, Magic and Methods. In this presentation, Karen discusses data model-driven database development from the point of view of the Data Architect, the DBA, and the Developer. She will cover topics such as "Who does what?", "Why are we doing this?", "Do I have to Use a GUI?" and "Just who do you think you are?". Finally, 10 tips for making model-driven database development successful in your organization’s culture and environment.
Session Level: Beginner
Karen López is Sr. Project Manager and Architect at InfoAdvisors, Inc. Karen is a frequent speaker at conferences and user groups. She has 20+ years of experience in project and data management on large, multi-project programs. Karen specializes in the practical application of data management principles. Karen is also the ListMistress and moderator of the InfoAdvisors Discussion Groups at www.infoadvisors.com.
I’m up against some fairly big name speakers, so I’m really hoping to see you in my session. Both of us can have a great time talking about data models. See you there.
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