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According to your schema, different analyses linked to different file
types will not cause redundancies in the list of extensions. However, if
you have multiple file types for an extension, then you will get
duplicates. I'm not sure how likely this is, but it's possible in a
generic situation, e.g.: .doc could mean a Word doc, or a WP doc. In this
situation, do you want one extension record or two. If you only want one,
then create a many-to-many resolution table between file type and
extension. If you are happy with two, then your schema is fine.
Of
course, you could always use a field array to hold the extensions, rather than
parsing a string field, but you will still get duplication. And that's not
very portable.
I have an interesting issue that I am
working through and was hoping to get some insight from the group. I will do
my best to explain the scenario and hope I do not confuse anyone.
We are storing data regarding some analyses
that are being run here. We also have a set of tables in which we store
information "about" the types of analyses being run. I am using these tables
to do a validity check on what file types (or input files) are acceptable for
a certain type of analyses.
I have the following tables:
An ANALYSIS table which merely holds the
name and some specifics about the type of analysis.
A FILETYPES table which stores information
about the types of input and output files for each analysis. We have chosen to
use file extensions as a way to identify a file type.
Some analyses can have multiple input and/or
output files so I have linking tables between the ANALYSIS and FILETYPES
table.
My question is due to a recent development.
Apparently when an analysis is run the individual can specify what type of
file the output can be. Since these tables are holding the data regarding the
"form" of the analysis I must somehow show that each analysis can result in
various filetypes. I thought I had done this and had an "extension" field in
the FILETYPES table. Now I am being told that each of these input or output
files can have more than one file extension.
My solution was to add another table to hold
the extensions. I think this is better than allowing extensions to concatenate
within a field in the filetypes table which was suggested by a programmer
here. Her intention was to parse the field. I prefer a more
"appropriate" solution, but I am not convinced mine is the best solution since
there will be some repeating data in the extensions table. Various analyses
can be associated with the same file types so the extension field in the
extensions table will have repeating values.
I have attached a small schema with these
few tables to assist with your understanding our issue.
I would appreciate suggestions.
Thank you,
Jodi Kanter
_______________________________
Jodi
L Kanter
BioInformatics Database Administrator
University of
Virginia
(434) 924-2846
[EMAIL PROTECTED]
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