Thanks Kevin. Nice clear explanation.


> I know what I think "Design Pattern" means, but I'd like to hear other opinions.
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>Kevin, let me give you something from a different angle....
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>Suppose I need to do something in SSIS - let's say I need to run a job that will scan all four product brands (where there's a brand manager for each one), read all the orders that have been processed since the date of the last job, and send an email to all four managers with summarized sales information (on what's been processed).
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>I step back and realize that 6 months ago, I had to do something quite similiar in SSIS....and had to go through the learning curve back then, to figure out how to use the SSIS control flow and data flow tasks to solve the issue. But now that I'm wiser than I was six months ago, I recognize that the new problem is one for which a previous approach can be used. So obviously, I'll be much more productive the 2nd time around, because I can take the approach I previously used.
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>Of course, some tools are better than others in terms of modularity and reusability. Depending on the tool, I may have to "repeat" some code - yes, it can suck, but at least you're still more productive than the first time.
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>Now, there are "design patterns" that relate to specific products (like the design pattern for SSIS above, which is one generally recognized by SSIS developers), and then there are more general patterns that are independent of any one tool.
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>But they all have something in common: a reusable approach to future problems where the problems are similar (in part or in full) to the original problem for which the original solution was built. The reusable approach might employ templates, reusable functions, common steps, etc.
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>Developers use "mini-patterns" all the time...in T-SQL when you need to do a nested TOPCOUNT....in C# when you need to create a factory...in SSRS when you need to deal with variable-length selections, etc.
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>The biggest key to using patterns? Recognizing right away that the current problem "feels like" a previous problem for which a set of steps led to the answer.
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>The links that Craig mentioned are good ones. Just wanted to throw this in as well.