8.2.8.3 Data Dictionary (DatD)

  Datenkatalog

Contents		Introduction Document Index Document Structure Links to the V-Model Mailinglist

Introduction

The input information for the Data Dictionary is delivered by the SW Architecture and SW Design. The Data Dictionary must contain the identifiers, the characteristics and attributes of the data structures and its elements (data description). Also important is information dependent on the implementation (data realization).

Such a product exists for each project.

Document Index

Document Structure

1. General Information

2. Data Description

• identification
  unique identifier of the data elements chosen in accordance with the conventions of the programming language and project rules for identification in the CM Plan
• long name
  the long name describes the content and the use of the data elements
• relations within a data element
  e. g. structuring into record-field-item, identifying key, etc.
• relations to other data elements
  e. g. redundancy, dependencies with regard to contents or time
• physical unity and normalization
  Decisive for processing a datum is its physical unity. Is a temperature given in Centigrade, Fahrenheit, or Kelvin? A distance given in kilometers or miles?
• refinement
  identifiers of data elements are given into which the (complex) data is structured
• defining SW Component/SW Module
  A data element is only defined by a SW Component or SW Module. The identifier is given here.
• referencing SW Component/SW Module
  All SW Components and SW Modules referencing (using) the data element are listed by giving its identifier and kind of reference:
  • read access
  • write access

• plausibility/integrity
• special characteristics and attributes

3. Data Realization

• data type and size
  in the case of scalar data: e. g. integer, real, char, and number of digits,
  in the case of composite data: e. g. record, array, and description of individual fields analogously to scalar data
• range and domain
• precision
• default setting
• access
  kind of access (e. g. sequential, indexed) and identifying key
• life time
  generation times and frequencies
• memory space requirements
  calculated from data type and format, while considering HW dimensioning
• location
  If memory has to be allocated statically the addresses are taken from the cross-reference listings of the compilers and/or linkers.
  It is to list the start address; for parts of data elements the address relative to the beginning of the structure must be given. A note is required if a relative address is concerned.

Links to the V-Model Mailinglist

This page online  •  GDPA Online  •  Last Updated 18.Ago.2003 by C. Freericks