Data Names.
HPM discusses some important aspects of naming things like tables
and fields in databases.
- make them meaningful
- more likely name them so they have
meaning to people in the organization
- name them so that other people
looking at the data will have much more sense of what is
contained
- critique the following
- customer_first_name
- sales_rep_last_name
- fn
- $$$
- cost_wholesale
- ss
- h_p
- phone_home
- customer_phone_home
- be unique
- be readable
- dangerous to use upper and
lower case to distinguish things on some
platforms
- customerfirstname
- CustomerFirstName
- customer_first_name
- cnf
- compose them using words
from an approved list
- be likelier to be the
same name others would choose
One author suggests this
list
- prepare a
definition of the data
- remove
insignificant or illegal words
- having an AND
or OR likely means you should
atomize further
- arrange the words
in a meaningful, repeatable way
- assign standard
abbreviations when meaningful
- make sure the
name doesn't already exist in use
elsewhere
Data Definitions.
A
term
is a specific word or phrase that
has meaning for the organization.
- course
- section
- showing
- rental
car
- apartment
-
reservation
- summer
camp
A
fact is an
association between two or
more terms.
- a
passenger may
reserve a flight
- a
child may be
registered for a
summer camp
- a
client may be
scheduled for a
showing
What constitutes
good definitions?
-
look for
data objects
and their
definitions
in similar
places to
business
rules
-
diagrams can
be very
helpful
-
try to
capture
subtleties
-
reflect
special or
exceptional
conditions
-
examples
-
determine
-
where
-
what
-
who
-
how
-
data are
created/calculated
in the
organization
-
is the
data
static
or
dynamic
-
is the
data
singular
or
plural
in
atomic
form
-
who
determines
the
value of
the data
-
who owns
the data
(controls
definition
and
usage)
-
whether
the data
is
optional
or if
empty
values
will be
allowed
-
whether
the data
can be
broken
down
into
smaller
atomic
parts
Many
people
say, "He
who
controls
the
meaning
of the
data,
controls
the
data."
The book
discusses
many of
the
difficulties
of
defining
a
"student"
- prospect
- applicant
- admitted applicant
- matriculated student
- continuing student
- former student
- graduate
You might also think about the difficulties associated with "passenger"
- reservation
- ticketed
- has assigned seats
- boarded
- rebooked
There are plenty of worse situations where you might not have all that much experience. Think of "patient" or "member". |