The Ralph Kimball’s methodology stands out for being, in general, with the most detailed methodologys, considering the stages of: (a) planning, (b) requirements gathering, (c) functional architecture, (d) database design, (e) end-user applications, (f) audit the data and (g) use, support extension and the Data Warehouse.
The development life cycle starts with planning, which can vary from company to company. It is one of the most critical activities for the quality of surveys and definitions will affect the project as a whole.
The main result of this phase is a Project Plan, with the data collected such as the justification of the project, costs involved, identification of project members, specifying the project schedule and the various stages and activities of the DW.
The business requirements phase are defined user key business factors, essential for the next steps. This phase is characterized by identifying and preparing the interviews of staff, selection of interviewers to each interview, analyze the results of each interview and Project Plan review. Second, the technical architecture design phase is one of the most important in DW design, which defines a high-level architecture (internal and external area), and the specification of the technical infrastructure and components needed to allow the creation of DW . In phase
selection and installation of products consists of performing research, study and selection of products related to construction of a DW, prototype development for a better evaluation of the functionality of the software and its acceptance by the end user, as well as design review.
The dimensional modeling step is to aggregate the data collected on the business requirements phase to develop a data model. During this phase it is also carried out to analyze the various data sources in order to identify those having the data necessary to satisfy the data model as well as specify search for the best among these data sources. This analysis includes the following activities:
• Identification of candidate data sources, checking details such as OLTP system which integrates platform (egUNIX, Windows NT, etc.), physical file structure (eg, flat files, Oracle, Excel, etc.), volume data ( eg number of transactions per week, etc.), identification of primary and foreign keys and characteristics of the data fields (eg data type, length, precision, etc.);
• Study of mapping data of the candidate sources for the data destination tables;
• Estimated number of rows or records of candidate data sources.
The physical design stage are carried out following definition standardized names activities to the objects of the database, implementing the physical design, creating objects of analytical database and the development of an initial plan indexing, aggregation and partitioning .
The design and development phase of organizing data area concerns the fundamental activities to be performed in DW: to extract, transform and load data. The main activities which comprise this phase are the creation of a high level that represents the flow of data from source systems to the analytical target database architecture, testing and choice of third-party tools or development of specific programs for the achievement the data organization of activities and details of the high-level architecture, determining, for example, which tables and in what order will be held, the extraction activity, transform and load, which the processing activities to be carried out in the various tables, etc.
In phase specifications of end-user applications should be made to identify priority areas and, from these, define a standard set of applications for end users, since not all users who need to have access “ad hoc” to DW data.
At the stage of development of end-user applications are developed the necessary applications according to surveys conducted in the phase of end-user applications specifications. ” The selection of the reports development environment and the development of maintenance procedures and updating of end-user applications, are activities which comprise this phase.
The release phase of DW is basically comprised of the following activities to assemble the verification plan the infrastructure, training strategy of end users, support strategy to the end user, version upgrade plan DW, complete testing system and availability of DW itself to end users.
Finally, In the DW maintenance and growth phase it is composed mainly by the ongoing support and user training and technical infrastructure maintenance, and monitoring of consultations held by end users, data organization’s performance and the continued success of DW.