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

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)

Data Dictionary Notation

Notation

=

+

[ ]

{ }

( ... )

* ... text ...*

n

Meaning

is composed of

and

either-or

n repetitions of

optional data

delimits a comment

Data Dictionary Example

telephone numberintegrated

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

Control Flow ModelCFD 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.

CFD for Safe Home

State Transition Diagram

Process Activation Table