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CBAP Tutorial | BABOK Technique | Data Dictionary

CCBA CBAP tutorial on Data Dictionary

In this CCBA CBAP tutorial on Data Dictionary, we will cover the basics of this 10.2 BABOK v3 technique. Data dictionary may not be a commonly used vocabulary in your day-to-day business analysis world, but it is an important concept.

In this tutorial on data dictionary, I will try and provide a conceptual understanding of data dictionary with examples. This is part of our CCBA CBAP Study guide for CCBA and CBAP preparation course.

What is Data Dictionary?

IBM Dictionary of computing defines data dictionary as

“A centralized repository of information about data such as meaning, relationships to other data, origin, usage, and format”

A data dictionary is also referred to as metadata repository. It comprises of information about the primitive and composite data elements.

A landline number is an example of a composite data element and it comprises of primitive data elements like ISD Code, STD Code, Area code etc. Let’s consider a complete telephone number in India, it looks as follows:

+91 22 2857 1200

This number comprises of multiple information as shown below:

Basic Element Name Any other name Type of values Description
ISD Code Country Code Number The international dialling code for the country
STD Code City Code Number The country’s city code
Area Code Area Code Number Local telephone exchange number
Telephone Number Telephone Number Number Actual phone number
Complete Telephone Number = [ISD Code + STD Code + Area Code + Telephone Number]

 

The table above describes primitive data elements and the composite data elements. This table is an example of data dictionary.

Purpose of Data Dictionary

Data dictionary is used to create a standardized representation of data elements for a given project or projects and for its stakeholders. This helps in having a common understanding and representation.

Without having a data dictionary, data can have multiple interpretations in a system. This may lead to different representations. For example, one developer may present a phone number as one value (allowing numbers and ‘+’ sign) and other one may present it as a combination of multiple fields. This leads to bad user experience.

Please note that data dictionary is always created for a context (a project). A composite data element may be relevant for one project but may not be for the other.

For example, if the application under development is for customers across the world, the ISD code is a relevant part of the telephone number. We have created the data dictionary for an application with ISD number.

But, if the application is to be used only in one country, the ISD code has no relevance and should not be part of the data dictionary.

Formats for Data Dictionary

Multiple formats can be used to represent a data dictionary. BABOK v3 suggests the following format:

Data Dictionary

We can use any format for representing the data dictionary as long as it is consistent across the artifacts.

Elements of Data Dictionary

As per BABOK v3 guide, the primitive data elements should have the following information:

  • Name: A meaningful name to the element so that it be recognized uniquely.
  • Aliases: Alternate or commonly used term used for the data element, different from Name
  • Value/Meanings: Represents data types (like number or text), size, list of values (if applicable) etc
  • Description: More details about the data elements for the specific project/context

Composite Elements may be:

  • Sequences: A composite element comprises of multiple primitive data elements. These elements could be arranged in a sequence i.e. coming one after the other as in the telephone number. A ‘+’ sign is used to represent that as shown below:

[ISD Code + STD Code + Area Code + Telephone Number]

  • Repetitions: When one of the data elements gets repeated multiple times. A ‘{ }’ is used to represent that:

Invoice = Invoice_number + Date + {items-ordered} + Sub-total + Sales-Tax + Total due

  • Optional Elements: A composite data element may also have optional elements. Optional elements are represented by ‘( )’.

Customer_name = First_name + (Middle_name) + Last_name

 

Note: Care must be taken to create the data dictionaries as unnecessary and irrelevant data dictionaries can lead to limited or no realization of business value.

Data Dictionary Example – Online Payments

In this example data dictionary, a composite data element payment-data and primitive data elements are shown:

Data Dictionary Example

CCBA CBAP Study Guide

This is an extract from our CCBA CBAP Study guide based on BABOK v3. The study guide is created to help aspirants understand concepts with the help of examples. BABOK v3 guide is a comprehensive book yet does not provide practitioner’s perspective.

This study guide is a complimentary study material to BABOK v3.

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