The concept of data dictionaries and the requirements for them are covered by NCITS L8
Standards Section 11179
Specifically, 11179-4 states:
A data definition shall
1. be unique (within any data dictionary in which it appears)
2. be stated in the singular
3. state what the concept is, not only what it is not
4. be stated as a descriptie phrase or sentence(s)
5. contain only commonly understood abbreviations
6. be expressed without embedding definitions of other data elements or
underlying concepts.
To further amplify these concepts, refer to Joe Celko's "Data & Databases: Concepts in
Practice", Morgan Kaufmann.
pp 345, in part:
<< For example, if an applicatin of "country name" were to list all the countries a
certain organization had trading agreements with, the application data element would
be called "trading partner country name".
The data value domain would consist of a subset of countries ...
In a registry, each of the dta element names and name components will always be
paired with its context so that we know the source or usage of the name or name
component. The goal is to be able to trace each data element from its source to
wherever it is used .... >>
[EMAIL PROTECTED] wrote:
>
>
>
>I was interested in the comment by someone at RBTI that not allowing
>duplicate column names was part of the Codd design. It had been a few
>years since I sat at the fire with my Codd book so I did that last evening.
>It seems to me if you look at the original 12 or actually 13 rules, rule #2
>seems to fit this situation. Rule #2 is usually referred to as the
>"Guaranteed access rule" and is usually worded something like this:
>
>"Every value can be accessed by providing table name, column name and key.
>All data are uniquely identified and accessible via this
>identity."
>
>Now I read that rule that there are 3 things needed to uniquely define a
>value or cell to the RDBMS. That is the table name, column name and the
>key. So my interpretation of this is that there is nothing in the Codd
>rules that says I can't have duplicate column names in differnt tables
>because the RDBMS should be defining cell locations by
>TableName.ColumnName.Key. And if my TableName name is different, then the
>RDBMS should be able to figure out what column I want; the one in
>TableName.
>
>So IMHO if the RDBMS is following Rule #2, it should allow us to name our
>columns anything we want.
>
>JeffS
>
>
>
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