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PROJECT PLANNING FOR THE DATA MODELER
of overtime. This tool can calculate how much time the tasks should take. If there is a relevant discrepancy between what the tool recommends and what the project manager expects, a meeting fairly quickly is in order. In this way expectations will be realistic from the inception of the project.
This chapter goes into two detailed examples on applying the Good Guess Estimating Tool. The first is a new data mart, which also involves making changes to the data warehouse architecture to support this data mart. This example demonstrates both a new application, which is the data mart, and an enhancement, which are the updates required to the architecture to support this data mart. The second example is an enhancement that needs to be made to a custom-built operational application. This example demonstrates when only a system enhancement is required.
If you visit the companion Web site, www.wiley.com/compbooks/hoberman, you will find blank templates for the tools in this chapter; additional tools; and more information about tools within this book, including empty templates that you can download.
What Is the Data Modeling Phase Tool?
You have been assigned to be the data modeler for a project, which has just been approved by senior management and is now ready to be allocated funds. The project manager would like to know what your involvement is going to be during each phase of the project. She is not as much interested in your deliverables at this point. That will come in the next iteration. She first wants to understand the high-level data modeling phases. You need to provide her with a comparison of where your work fits into the context of each software development life cycle phase.
The Data Modeling Phase Tool presents at a high level each of the data modeling steps and where they fit into the software development life cycle. It provides a number of benefits:
Assigns data modeling deliverables to sections of the project plan. Too often, we focus on looking for sections in the project plan where we can put or hide the logical and physical data model deliverables. In reality, there are many other steps in which the data modeler is involved. Each is part of a phase, and each phase has its role in the life cycle. For example, subject area analysis and subject area modeling are the data modeling phases that fit within the business requirements section of the project.
Offers a communication medium with the project manager. This tool can be reviewed with the project manager during the development of the project plan. In the opening story to this section, you can use this tool to meet with the project manager and help her understand where the data modeling phases fit within her project.
Provides context for many of the tools within this book. Each phase in this tool corresponds with one or more chapters of this book. It is a very good way to understand how the different sections of the book relate to each other. For example,
this tool documents that subject area analysis is discussed in Chapter 5, “Subject Area Analysis,” and subject area modeling is discussed in Chapter 6, “Subject Area Modeling.”
Becomes the starting point for the Phase-to-Task-to-Tools. The Phase-to-Task-to-Tools takes each of the phases in the Data Modeling Phase Tool and breaks them down into more detailed tasks. For example, subject area modeling is broken down into creating the Business Clean Slate, Application Clean Slate, and Early Reality Check data models.
Using the Data Modeling Phase Tool
The Data Modeling Phase Tool is divided into project sections with the corresponding data modeling phase. Table 4.2 is this tool with a description of each phase and the chapter(s) where the topic is covered.
The project definition includes everything in terms of project justification and scope. Why are we doing this project? What benefits do we expect from this application? Justification usually takes the form of a Request for Funding, or similar document, designed for management to agree on the value of this project. The scope is how this project fits in with other development efforts and existing applications. Much of this information usually is a guess at this point because complete subject area analysis has not been done yet, and therefore, the subject areas of the project have not been validated. There are times when this phase is not considered to be complete until part of the Subject Area Analysis phase is completed so that we know the subject areas and how they will be impacted by this project.
Table 4.2 Data Modeling Phase Tool
PHASE PROJECT DATA MODELING CHAPTER(S)
I Project Definition
II Project Planning Project Planning for Data Modeling 4
III Business Requirements Subject Area Analysis 5
Subject Area Modeling 6
IV Functional Requirements Logical Data Analysis 7
Logical Data Modeling 8,9,10
V Technical Requirements Physical Data Modeling 8,10