Computer-Aided Software Engineering (CASE) tools are used by system analysts, designers, and developers to capture information about business requirements, create a design for the data structures to fulfill those requirements, and generate front-end and server program code. CASE tools can automate much of the manual, repetitive, and error-prone work needed for system development, and can greatly increase the productivity, accuracy of the design, and robustness of the implementation.

System Development Life-Cycle

CASE Application Development Method (CADM) – 7 phases:
1. Strategy
2. Analysis
3. Design
4. Build
5. Test
6. Implementation
7. Maintenance

1. Strategy

The purpose of the Strategy phase is to formulate a basic description of the overall scope of the project and how the project will proceed. The entire focus is on the business. The goal is to gain a clear understanding of the business area’s goals, objectives, processes, direction, and needs in order to structure and document the vision of project. Results of this phase include strategy ERD, process flows, strategy document, cost-benefit analysis, and workplan.

Strategy Document is also referred as project charter, project definition document, and scope document. Strategy document outlines the scope of a project and defines an agreement about what the project is committed to deliver. It also includes the estimated budget, time frame, resources, controls, and standards within which the project must be completed.

2. Analysis

The analysis phase breaks logically into two parts: information gathering and requirement analysis.

Within the information gathering portion, techniques for getting at user requirements include interviews, questionnaires, and joint application development (JAD) sessions, along with reviews of the current system, the report audit, and user and system documentation.

In requirements analysis, we extract the system requirements form the information gathered and place them in an organized structure. This can be done at both the unit level and, ultimately, at the system level.

3. Design

The Design phase includes two broad subphases:
- Database Design
- Application Design

You should already have a complete ERD from the Analysis phase, but need to do the physical database design. The basic strategy of database design is to map entities to tables, making adjustments fo subsets, denormalization, aggregation, and summary tables.

At the simplest level, application design is the design of software, including the creation of structures that address modules, programs, procedures, navigation, internal controls, and security.

4. Build

In the Build phase, you build the database and application. The Build phase deliverables consist of the following:

- Unit tested application system
- Populated databases
- System documentation
- User documentation
- Help system and online documents

5. Test

In the Test phase, you develop a test plan that should describe not only test to be run but also how test failures or variances will be handled. Tests include unit testing, system testing, user acceptance tests, and training and documentation. Through this phase, the new system is formally tested.

6. Implementation

In this phase, the project team will rollout a system to production environment and provide adequate user support. The rollout/migration process involves transition period where the system is closely monitored and support is transferred from the project team to the system operation group.

7. Maintenance

Maintenance is a process that continues throughout the life of the system. A predefined process must be put into place to handle ongoing problems, modifications, and enhancements.

As for database design tools, there are many.  The most popular ones are:
Rational Rose (from IBM)
ERWin (from CA)
Oracle Designer (from Oracle)
PowerDesigner (from Sybase)

A typical answer could be:

“I mainly used ERWin for database design in my previous projects.  I used this tool to collect business entity data and did data modeling with entity relationship diagram, and then I used the tool’s function to build the logical database based on the ERD.  I also use it to help me in physical database design analysis and generate SQL scripts to build database objects such as tables, indexes, and views.  I’ve used ERWin for 4 years in Oracle and DB2 database design projects.  But when I worked on Microsoft SQL Server, I used the build-in Enterprise Manager to do data modeling and create ERD.”

“I have hands-on skills and experience in database design and data modeling.  In previous jobs I have worked as the technical lead to design large scale database systems in Oracle, Sybase, and Microsoft SQL Server.  I have experience in several database design tools such as Oracle Designer, PowerDesigner, and ERWin.  Using these tools I collected and documented user requirements, analyzed business rules and entities, created entity relationship diagrams, designed logical database based on the ERD, and generated SQL scripts to build the physical database., and configured the database server and setup the database.  I also used database design tools to reverse-engineer existing database when necessary.  Database design tools are very helpful for me to automate many tasks through the database design lifecycle, but in many cases I still need to fine-tune the design manually.  I also have experience in using design tools to create data repository for meta data management.  In one of my jobs I worked as the repository administrator responsible for building and maintaining Oracle data repository in Oracle Designer for our term members to work together in a common data design platform through database design phases.  ”

Suggested answer:

“I have 6 years of database design experience mainly with Oracle database and have been involved in over 10 database design projects. In these projects I’ve worked on analysis of business entities and data modeling, creating entity relationship diagrams, design the logical database such as converting entities and attributes into table and columns. I also worked a lot on designing the physical database such as analyzing storage usage and performance, designing tablespace and table partition, writing SQL scripts to create database objects like tables, views, and indexes. One of the databases I designed is for a Federal agency’s employee activity tracking system; it contains over 200 tables, about 50 views, and more than 150 indexes on an Oracle server in UNIX platform. I used Oracle Designer to assist most of my database design tasks.”

Enterprise modeling contains Data Modeling, Process Modeling, and Logic Modeling.  Optionally Physical Modeling may also be considered part of enterprise modeling.

The data model is a logical representation of the data or information as it is used within the enterprise.  Data modeling is realized by Entity Relationship Diagram (ERD).  The ERD is composed of entities, attributes, and partnership sets (relationships).

The process modeling is a high-level conceptual design for the business functions which access the data model.  Process model is presented by Data Flow Diagrams (DFD) and Functional Decomposition Diagrams (FDD).

The logic modeling is the processing representation of functions within the enterprise that operate against the data model.  The logic model is composed of Process Specification Diagrams (PSD).

Physical modeling is the process of taking the logical representation of data and the transaction analysis to analyze the performance of the transactions.  In general, database administrators (DBA) are involved in this process to allocate disk volumes, indexes, and other performance enhancements needed on the basis of the analysis.

UML stands for Unified Modeling Language.  The UML provides a language-neutral, tool-supported, well-documented standard for modeling systems such as web applications.  It enables system requirements, structure, and behavior to be succinctly captured and effectively communicated.

As explained by Duncan Jack in August 2005’s JDJ, UML is interpreted as:

• Unified: The result of unifying three leading approaches to system modeling in the 1990s
• Modeling: concerned with the simplified representation of system structure and behavior
• Language: A language, not a methodology.

The UML is not a methodology.  It is a diagram-based language.  This point is important.

The UML contains 6 structure diagrams and 7 behavior diagrams.  The most commonly used diagrams are:
- Use case diagram (behavior)
- Activity diagram (behavior)
- Class diagram (structure)
- Sequence diagram (behavior)