Reference Data and Data Modeling{4}


by Antonio M
This article questions whether a data model can truly specify all the design for a database.
The author of this article suggests that there a limits to what a data model can do and for
a database designer not to recognize these limits can lead to problems down the road of
database development. Some of these limitations is the use of Reference data and not being
able to illustrate this on a data model.The author further introduces the word Reference data
which is like a class of data that can have many meanings, in data modeling they usually contain
2 attributes(code and description). These reference datas are used  in  other
data found in a database. Reference datas are mostly used in help with
the physical design. The convenience of reference data is that you can add additional values
to an Entities attribute in a reference table. An example of reference data that was used
in this article was attributes of physician, nurse and patient in an entity called Hospital
Administration. Rather than having 3 attributes you can have one attribute called Role and
then reference that attribute to a Reference Data Table that will have the description of
Physician, Nurse or patient. This of course is all done in the physical level. The convenience
of this design is that it can be easier to make another role by just adding another value into
the Reference Data Table. The author further talks about the artificial divide between logical
design and the physical design and this can be a big problem for data administrators since
reference data values “embody database design.” According to the author the more reference
tables a data model contains the more it will depend on its physical design to specify its
implemented design.

This article was very interesting to read because it showed me the kind of gaps there can
be from going to logical design to the physical implementation design of a database. This
article also taught me about reference data and how it can be used through out the design of
a database.

Reference:
Chisholm, M. (2007). Data models are not database design. Information Management, 17(10), 45-45.
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