Tag Archives: Application Development

Meaningful Requirements Start Successful Data Projects

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To me, development projects fail or succeed in the first few weeks. Once a project starts off in the wrong direction, momentum and expectations tend to prevent a return to the proper path. With today’s wealth of database options each addressing exciting new possibilities, the right choice for the application’s data foundation plays a large part in steering a project to success.

At this year’s Enterprise Data World conference, William Brooks showed the relations among different data modeling approaches, in effect detailing how to derive nine different model types from a detailed conceptual entity relationship model. Mr Brooks’ presentation hinted at a way to correctly frame up your data direction early on in a project, setting the stage for success.

According to his presentation, called “Symmetry in Modeling Approaches“, the different model types — relational, graph, dimensional, JSON, XML, and so on — all represent different perspectives on the same data relationships. Each suits a different application, like dimensional for reporting applications, data vault for data warehouses, graph databases for multi-layered search, and so on. However, if properly constructed they all map back in predictable and specific ways to a normalized entity-relationship model.

I and others write that ER modeling should be integral to requirements definition, but Mr. Brooks’ presentation implies that ER modeling can also serve as the basis for application architecture as well. Continue reading →

Values and Behaviors of the Successful Agilist

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Of course, any discussion of Agile values starts with the Agile Manifesto. The first sentence declares that Agile development is about seeking better ways and helping others. Then, as if espousing self-evident truths, the founders present four relative value statements. Finally, they emphasize appropriate balance, saying that the relatively less valued items aren’t worthless: implying that they are to be maintained inasmuch as they support the relatively more valued items.

While there is value in the four relative value statements, I believe most successful Agilists value the first and last statements more. So to me, the core Agile values are continuous improvement, helping others, and balance.

There’s a lot written about Agile behaviors, but as I read most is geared toward scrummasters or managers, and most is about transitioning from the waterfall world. Starting from the premise that Agile methods are established, focusing on participants rather than managers, and based on the assumption that behaviors are grounded in values, this post details the values and behaviors I’ve observed of those who succeed as Agile team members.

Continue reading →

Escaping Teradata Purgatory (Select Failed. [2646] No more spool space)

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Also see the related post More on “Select Failed. [2646] No more spool space”

If you are a SQL developer or data analyst working with Teradata, it is likely you’ve gotten this error message: “Select Failed. [2646] No more spool space”. Roughly speaking, Teradata “spool” is the space DBAs assign to each user account as work space for queries. So, for example, if your query needs to build an intermediate table behind the scenes to sort or otherwise process before it hands over your result set, that happens in spool space. It is limited, in part, to keep your potentially runaway query from using up too much space and clogging up the system.

After briefly setting the stage, this post presents the top three tactics I use to avoid or overcome spool space errors. For the second two tactics I’ll show working code. At the end of the post you’ll find volatile DDL that you can use to get the queries to run. Continue reading →

Reporting Database Design Guidelines: Dimensional Values and Strategies

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I recently found myself in a series of conversations in which I needed to make a case for dimensional data modeling. The discussions involved a group of highly skilled data architects who were surely familiar with dimensional techniques but didn’t see them as the best solution in the case at hand.

I thought it would be easy to find a quick, jargon free summary of best reporting database design principles aimed at a technical audience. There were a number of good summaries (cited at the end of this post), but none pitched just right for this highly-technical-but-outside-the-data-warehouse-world crowd.

I wanted to raise the dimensional model because, for most business reporting scenarios, it not only delivers on reporting needs, but also helps report developers handle changes to those needs as a side effect of the design.

So these are the notes I prepared for the conversation. They helped us all get on the same page, hopefully they will be useful to others: Continue reading →

Analytics Requirements: Avoid a Y2.xK Crisis

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Even though it happens annually, teams building new visualizations often forget to think about the effects of turning over from one year to another.

In today’s fast paced, Agile world, requirements for even the most critical dashboards and visualizations tend to evolve, and development often proceeds iteratively from a scratchpad sketch through successively more detailed versions to release of a “1.0” production version. Organized analytics teams evolve dashboards within a process framework that include checkpoints ensuring standards are met for security, reliability, usability, and so on.

A reporting team can build a revolutionary analytics capability enabling unprecedented visibility into operations, and then, if year turnover isn’t included in requirements, experience embarrassing errors and usability challenges in the January after initial deployment. In effect, the system experiences its own Y2.xK crisis, not too different from the expected Y2K crisis 16 years ago. Continue reading →

Protect Your Culture: Screening for authoritarian project leaders

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Bugs BunnyIt’s fashionable today to talk about the risks of authoritarianism in the political sphere. I’m not going to speculate on that, but such talk got me thinking about the same tendencies among IT project leaders. What is an authoritarian personality? (Yes, that’s actually a thing.) Is it truly antithetical to a healthy project? If so, how can you screen for it in hiring?

Recently, ArsTechnica ran an article that offers a survey of research on authoritarian personalities conducted since the 1940s. The bottom line for us is that those with authoritarian tendencies more often Continue reading →

More on the Agile Architect: Process and Knowledge Transfer

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webscrum_2444372bI’ve written about groupthink-related quality challenges on Agile projects, and the architect’s role in preventing groupthink from degrading quality. I’ve seen other risks related to the cohesion and potential insularity of successful Agile teams, and the architect is also well positioned to help prevent these: a tendency to neglect setting up and documenting repeatable processes, and a similar tendency not to share of knowledge and lessons learned outside the Agile team. Continue reading →

Assumptions: A Key to Technical Leadership

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DonkeyThere’s an unfortunate and rather rude saying about assumptions that I’ve found popular among IT folks I’ve worked with. I say unfortunate because, to me, assumptions that are recognized early and handled the right way are a key to successful projects. Technical players who use assumptions well can help set projects on the right path long before they go astray.

Sometimes on waterfall and hybrid projects technical players are asked to estimate work early, before requirements are complete. My instinctive reaction is not to provide an ungrounded estimate, but that’s not helpful. The way to handle this uncomfortable uncertainty is to fill out the unknowns with assumptions: detailed, realistic statements that provide grounding for your estimate. Continue reading →

GIGO: Data Quality Guidelines for Application Development

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There’s consensus among data quality experts that, generally speaking data quality is pretty much bad (here, here, and here). Data quality approaches generally focus on profiling, managing, and correcting data after it is already in the system. This makes sense in a daGIGOta science or warehousing context, which is often where quality problems surface. To quote William McKnight at the first of those sources:

“Data quality is no longer the domain of just the data warehouse. It is accepted as an enterprise responsibility. If we have the tools, experiences, and best practices, why, then, do we continue to struggle with the problem of data quality?”

So if the data quality problem is Garbage In Garbage Out (GIGO), then I would think that it would be easy to find data quality guidelines for app dev, and that those guidelines would be lightweight and helpful to those projects. Based on my research there are few to none such sources (please add them to the comments if you find otherwise).

So, all that said here’s my cut at app dev data quality guidelines by project activity: Continue reading →

Lynchburg SQL Server User’s Group 10/30

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Liberty-UniversityYesterday I had the pleasure of presenting “The Business End of Data Modeling” for the Lynchburg SQL Server User’s Group. It was a great time, thanks for having me out!

I’ve linked the presentation below, please comment here or shoot me an email if you have comments or questions.

BusinessEndOfDataModeling20141030