The document describes a data dictionary, which includes:
1) A notation for describing the content and values of data that a software system will process and create.
2) Information about where and how data items are used.
3) A repository that also contains relationships between data items.
4) Best developed using CASE tools to represent the data dictionary notation and examples.
Oppenheimer Film Discussion for Philosophy and Film
What is a DATA DICTIONARY?
1. ry
The Data Dictionary
a quasi-formal grammar for describing the content
of data that the software will process and create
a notation for describing control data and the
values that control data can take, e.g., "on," or "off"
a repository that also contains "where-used" / "how
used" information
a notation that can be represented manually, but is
best developed using CASE tools
2. Building a Data Dictionary
Name:
Aliases:
Where used:
How used:
Description:
Format:
the primary name of the composite data item
other names for the data item
data transforms (processes) that use the
composite data item
the role of the data item (input, output,
temporary storage, etc.
a notation for representing content (presented
on next slide)
specific information about data types, pre-set
values (if known)
3. Data Dictionary Notation
Notation
=
+
[ ]
{ }
( ... )
* ... text ...*
n
Meaning
is composed of
and
either-or
n repetitions of
optional data
delimits a comment
4. Data Dictionary Example
telephone number
integrated
office
phone
system
Name:
Aliases:
Where/How
us ed:
Description:
Format:
telephone number
phone number, number
read-phone-number (input)
display-phone-number (output)
analyze-long-distance-calls (input)
telephone no. = [ local extension | outside no. | 0 ]
outside no. = 9 + [ service code | domestic no. ]
service code = [ 211 | 411 | 611 | 911 ]
domestic no. = ( ( 0 ) + area code ) + local number
area code = *three numeral designator*
Build the requirements dictionary:
alphanumeric data
system output
5. Control Flow Model
CFD is a diagram to describe the control flow of a
business process, or program.
Begin by stripping all the data flow arrows from the
DFD
Events (solid arrows) and control items (dashed arrows)
are added to the diagram
Add a window to the CSPEC (contains and STD that is a
sequential specification of the behavior) for each
bubble.