Identification of Functional Components

The technique of functional modelling (functional analysis/ functional decomposition) is used to model the relationship between the transactions and the application as a whole. The transactions are mapped onto a functional hierarchy of the application under the business activity to which they contribute.

The following criteria is used, where possible, to check each task to determine if it is a unique elementary process (logical business transaction). It is counted as a unique logical transaction when:

• it has processing logic (editing, validation etc) different from other similar transactions
• it accesses a unique combination of fields and files
• on completion, it leaves the business in a consistent, predictable state
• it is user recognisable and definable
• it is created by business requirements and not the technical requirements of the chosen solution
• it is logically independent of other transactions (although it may in some cases be triggered by another transaction)
• it is logically triggered by an external event
• it achieves a business objective, not a technical objective

The technique of data modelling (information engineering, entity relationship diagramming) is used to identify the data and the relationship between the data. The data files are then mapped to the transactions on the hierarchy which access them.

Data files are logical master groups of data from a business user perspective. They are a group of data that tends to be created as a ‘set’ although parts of the data may be modified independently. They may be a business reference file e.g. Currency Details which are referenced by transactions or business entities maintained by the business transactions.

Data Files do NOT include files created for quality, technical, performance, security, navigation reasons. Data Files are permanent groups of data, they are not stores for temporary data.