RE: SQL Existence Check

[Vernon Hamberg <vhamberg@xxxxxxxxx>]

I thought it was pages of keys. Otherwise, access by index only is pretty
meaningless, since it's supposed to never touch the table itself.

At 11:59 AM 3/12/02 -0500, you wrote:
> >From: Vernon Hamberg [mailto:vhamberg@attbi.com]
> >The other factor here is that SETLL will have less IO than CHAIN
>
>That was my understanding too, however I could never reconcile that with my
>understanding of the Binary Radix Tree. Doesn't a B* tree store only enough
>of the key to identify which page of the table the row is on? If so I can
>get a negative hit from the index itself, but I must go to the table to get
>a positive hit, no?
>
>Given a table with Name a key and the following rows:
>
>Walden
>Mike
>Walter
>Bill
>
>Wouldn't I have three top level index pages, one for W, one for B and one
>for M pointing to three pages in the table. If so, I know from the index
>that "George" is not on the table, but I need to look at the table to find
>out if "William" is a valid row.
>
>Where is my understanding of B* broken?
>
>-Walden
>------------
>Walden H Leverich III
>President
>Tech Software
>(516) 627-3800 x11
>(208) 692-3308 eFax
>WaldenL@TechSoftInc.com
>http://www.TechSoftInc.com
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