The DDD concept that you pick the DB last & that the DB doesn’t matter is like saying you pick the data structures last & they don’t matter.
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@kellabyte I agree, even though I’m not really sure DDD advocates that. Also, true for most other tech decisions, too.
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@stilkov Wasn’t there an entire chapter about abstracting away technical details and strategic design?
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@kellabyte @stilkov that's not how I've read it. It says that the model is more important. Learn it first and pick the db later
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@jeppec @kellabyte I agree – my reading is it advocates separation of concerns from a modeling perspective. Uncle Bob’s take is different.
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@stilkov @jeppec anti corruption layer: “insulating the domain layer from knowing the existence of the other system.”
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@kellabyte @stilkov yes - it's for integrating with another system. I.e. Not something you use internally to abstract away the db
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@jeppec @stilkov Can the anti-corruption layer translate and adapt for the mismatch in guarantees? No it cannot.
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@kellabyte @stilkov of course it cannot, thats also not what the pattern says. I feel like you WANT to misread the intentions?
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@jeppec @stilkov “insulating the domain layer from knowing the existence of the other system.”
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Replying to @kellabyte
@kellabyte @jeppec It’s a very common thing, e.g. when you build an adapter to various different external accounting systems.

Oct 19, 2015 · 6:00 AM UTC

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@kellabyte @jeppec In that case, you don’t want to introduce, say, an SAP dependency into your core domain layer. Surely reasonable?
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@stilkov @jeppec Agreed but my point is that the guarantees and tradeoffs that SAP introduce impact.
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Replying to @stilkov
@stilkov @jeppec Yeah I know. I’ve seen tons of them. Guess what, those systems are riddled with distsys bugs.
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@kellabyte Then taken to the extreme, what you’re saying is there can be no isolation between connected systems *at all*. @jeppec
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Replying to @stilkov
@stilkov @jeppec web apps talking to a DB directly are full of distsys bugs due to reduced isolation. Imagine web apps + external API’s?
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