While thinking about my reply to Appropriate amount of abstraction, I dug a little more into the Law of Demeter than I had previously. It occurs to me that Demeter shouldn't apply to object-relational mappers.

Relational databases are just that: relations. Crawling through multiple-table joins is normal in a reasonably complex database. When you translate these joins into an object-relational mapper like Class::DBI, these naturally break Demeter. But Demeter comes from the OO world, and joins come from the relational world. I don't think there is a good way to recincile these viewpoints that will satisify Demeter.

Of course, many say that object-relational mapping is a flawed idea, and this probably forms a good argument for that position.

Update: Minor spelling fix (s/mutiple/multiple/).

"There is no shame in being self-taught, only in not trying to learn in the first place." -- Atrus, Myst: The Book of D'ni.

In reply to Law of Demeter and Class::DBI by hardburn

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