Ping: dawn, some mvl questions

From: Kenneth Downs <knode.wants.this_at_see.sigblock>
Date: Sat, 20 May 2006 07:58:59 -0400
Message-Id: <stc3k3-i92.ln1_at_pluto.downsfam.net>



Dawn,

One of my practical objections to MVL is that it obscures data. I'd like to know what you might offer to that objection.

I am in the school of thought that says that if you need a list, make a table, that's what the RM is for. Then if you need to manipulate that list, use SQL. All common patterns, such as header-child for orders, lists of flags or dates, and so forth can all be done with child tables.

When an MVL comes, which is fully supported in the PostgreSQL database that I use, I notice you end up needing a different word for everything. You can't just query a child table, you need new operators like "ANY OF {field} = " or something along those lines.

This is where my objection comes up. Now I need an alternative syntax. But what if the values in that list come from a table, how do make foreign key, and what if I want to populate a cross-reference? When does it end? How much alternative syntax will I need?

The question becomes, what do I gain that I don't get from a child table that is worth the price of a "different word for everything" when I deal with these lists?

-- 
Kenneth Downs
Secure Data Software, Inc.
(Ken)nneth_at_(Sec)ure(Dat)a(.com)
Received on Sat May 20 2006 - 13:58:59 CEST

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