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    <p>I'll see if I can do my best to answer your questions succinctly.</p> <blockquote> <p>1.At what point is building a data warehouse an option worth considering? In other words, what telltale signs, metrics, or other criteria should I be looking out for that might indicate that a standard transactional environment is no longer sufficient?</p> </blockquote> <p>a. If you find that reporting and monitoring are impairing the performance of your production system and/or an offline data store.</p> <p>b. If you find that getting answers to your business questions requires building a lot of complex SQL each time. </p> <p>c. If you find that every time you make a change to your transactional schema, you have to go back and rework all of your reporting queries.</p> <p>d. If you want to bring together data from multiple sources.</p> <blockquote> <p>2.What are the alternatives to a full-on data warehouse? Denormalization in the transactional database and the bog-standard replicated "report server" are two that come to mind; are there any others I should explore before committing to the DW?</p> <p>3.Why is a data warehouse better than said alternatives? If the answer is, "it depends", then what does it depend on?</p> </blockquote> <p>I'll answer these together. I wouldn't think of a data warehouse as an all or nothing venture. It's simply a concise phrase that means "storing your data in a way that allows you to more easily and quickly answer business questions."</p> <p>Transactional databases are designed to efficiently interface with applications. Data warehouses, data marts, operational data stores and reporting tables are built to efficiently interface with people, if that makes sense.</p> <blockquote> <p>4.When shouldn't I attempt to build a data warehouse? I'm skeptical of anything declared as a "best practice" irrespective of context. Surely there must be some scenarios where a DW is the wrong choice - what are they?</p> </blockquote> <p>Good question. If your transactional system provides you with sufficient insight into your business, you probably do not have a need for warehousing. </p> <p>If you only have one source of data and performance is not a problem, you can probably gain insight from creation of simple reporting tables.</p> <blockquote> <p>5.Are there any practical examples I could look at of systems that were improved by introducing a data warehouse? Something that would explain to me, end-to-end, what sorts of decisions or analysis they needed the warehouse for, how they decided what to put in it, and how the warehouse ended up fitting into the larger environment? I don't want a contrived "let's make a cube out of the AdventureWorks database" - the implementation is irrelevant to me, I'm interested in the specifications and designs and overall thought process that were involved.</p> </blockquote> <p>That's a big question that would take far more space than I'm allotted here.</p> <p>On this one, I can point you to a few places that might provide the insight you seek.</p> <ul> <li>"Implementing A Data Warehouse: A Methodology that worked" by Bruce Ullrey is a book documenting one man's journey to building a data warehouse. It's not highly polished, which gives it more realism. It reads like a journal with lots of models and other visuals that illustrate his efforts pretty well.</li> <li>"Business Intelligence Roadmap" by Larissa Moss. Standard fare. Walks you through the process of building a BI practice at a high level.</li> <li>"The Profit Impact of Business Intelligence" by Steve Williams gives a number of case studies that show the value of building data warehouses. </li> </ul>
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    1. POData Warehouse Considerations: When and Why?
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    1. COvery very good ... I'd add one link to question 5. Look at MS Project Real (http://technet.microsoft.com/en-us/library/cc966416.aspx). It is a practical implementation (with data/ETL) of a fairly large DWH with reasoning/critque
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