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Re: object algebra

From: Neo <neo55592_at_hotmail.com>
Date: 10 Mar 2004 11:43:12 -0800
Message-ID: <4b45d3ad.0403101143.16c3cbba@posting.google.com>


> > These two statements contradict each other:
> 1) In TDM/XDb1, there is no meta-data about the data in the db.
> 2) Data added to the db doesn't have to conform to any design-time
> "schema" but the added data itself defines the current "schema".

In TDM/XDb1, there is no meta-data about the data as in RDM. For instance in RDM sytem/hidden table(s) indicate:

a) what tables exist in db.
b) what attributes exist in each table. 
d) the type of each attriblute. 
c) which key of tableX is related to which key of tableY. 
There is meta-data like the above in TDM/XDb1.

In TDM/XDb1 there are no stored "schemas", but a "schema" of any level of generalization can be derived from the current data. Unlike RDM, TDM only assumes the following about future data: new things will be related to existing things. Received on Wed Mar 10 2004 - 13:43:12 CST

Original text of this message

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