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Is there a benefit to creating a very generic data model for a Rails 3 Project?

Answer 1

+3 A:

No.

Seriously

No.

at least not in a SQL database.

If you want to use Cassandra or a NoSQL database, that's exactly how everything is stored.

Read my answer here and Read this

Think of a SQL Table with First Name, Last Name, and Birth date

Find all the LNAME = Page older than 30.

in one table it's

SELECT FNAME, LNAME, (SYSDATE - BDATE)/365 age FROM people WHERE LNAME = 'Page' and BDate < SYSDATE - 30*365

Now try it in an EAV

Post your answer.

Stephanie Page 2010-10-15 15:43:35

I won't, but I bet it would have an EXISTS in it. I guess they all would. Thanks Steph ;-)

AKWF 2010-10-15 16:02:42

But here's my real problem. There are LOTS of potential product attributes that are compound in nature. Like some value coupled with a language_code or a unit_of_measure. It seems crazy to have each of those as their own model or even as explicit attributes. The data standard I'm trying to handle has over possible attributes, some of them compound. But each product will only "care" about 50 or so.

AKWF 2010-10-15 16:06:05

AK, That's a HUGELY important point... CARE, Care about 50. That means filter on or group on, etc. First, (i don't believe this because I'm a data addict) but why does your db have data no one cares about. Yes, I'd keep it to. And in those cases, you'd have to think about what you're going to do with it. If you're keeping it just to keep it, shove it in a CLOB or XMLType. Then when the 51st one becomes CARED for, add that column and do an update of the column from the XML Store.

Stephanie Page 2010-10-15 19:32:20

Also, there's nothing wrong with vertical partitioning or PK-FK tables. You'd have one table with ID, Name, Category, etc... whatever is REALLY common. Then say you descriptions in 10 languages. So it's a 1-many between Product and description... create a description table with ID, LanguageCD, Description. etc... rationalize each property and how it fits in, how shared it is, is it really 1-1 or 1-many...

Stephanie Page 2010-10-15 19:39:25

Now, one more thing. Is this used to populate a website or is this for something like an inventory system?

Stephanie Page 2010-10-15 19:40:06

It's a combination management and display platform. What I have done today is broke out what I thought was very important as a stand-alone model, and put the data that is not common across all products in a sparse matrix. If something ever becomes "important", I can always extract that into a model.

AKWF 2010-10-15 20:12:57

Your posts have been hugely helpful!

AKWF 2010-10-15 20:13:31

by display do you mean reporting or displaying to an ecommerce site? Let's just say, if you want to make this really fast for ecommerce we'll need to discuss some further steps. I helped a friend build a very, very fast, online pet store.

Stephanie Page 2010-10-15 21:50:51

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Is there a benefit to creating a very generic data model for a Rails 3 Project?

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