Data Template - Introduction
Last Updated on Tuesday, 13 April 2010 13:57 Written by Phil Bailey Monday, 12 April 2010 21:11
Purpose of the Template
The purpose of the template is to provide a structured approach to documenting a data model that describes the data changes to an existing or the data model required for a new system.
The production of a conceptual data model allows the analyst to agree the data that the IT system requires from a business perspective. A conceptual data model allows the business to clearly define:
- The data entities that the system needs to store data about
- The relationships that exist between each data entity that has been identified
- The specific data that we need to capture about each data entity
- The business rules that apply to the data and the relationships so that the system operates in the way the business needs
A model is a better way to define data than listing the data required in the functional requirements specification. Where data changes are required we should look to produce a conceptual model with the business to explore their data needs and to make sure that all the rules that relate to the data has been understood and therefore can be conveyed to the IT developers in the requirements.
Data modelling is an essential part of the analyst’s toolkit and for the majority of projects should be a mandatory deliverable. All analytical approaches for IT change recommend that a data model is produced and is a recommended output by ISEB and the IIBA
In what circumstances should we use this template?
It is recommended that we produce a data model in the following circumstances:
- Where we need to specify the data for a new system
- Where the changes made to the data held in an existing system impacts on more than one data entity or we are adding a completely new data entity to the system
There is of course nothing stopping you producing a data model for even the smallest data change if you feel that is appropriate for the project that you are working on.
What information does the template allow you to capture?
The template has been designed to allow you to capture the following information about a data model:
- A diagram that captures the details of the various entities that the business need to capture information about and the relationships that exist between them
- A textual description of the diagram to ensure that the reader of the document can understand what the diagram is expressing
- A series of data tables, one for each entity, which defines the individual data items that need to be captured for each one, together with any rules the business wish to apply to that data.
- To specify any static data that needs to be captured, Typically this will be used to populate drop down lists that restrict the data captured in a particular field
- To specify any data that needs to be pre-populated in the database so that the system is ready for use when it is launched to the business.