Relationship Management Methodology (RMM): A Brief Introduction
CSC340 Assignment 4:Research Question 11
Submitted by Gajen Pararajalingam
To Professor Eric Harley
RMM is a systems development and project management technique used mainly for the design and construction of hypermedia applications. Without guidance WWW applications can evolve into an entangled spaghetti-like collection of HTML pages that are hard to access and costly to maintain. Examples include product catalogs, e-commerce gateways, design manuals and interfaces to traditional database or legacy applications. These are highly structured and have high information volatility (i.e. require frequent updating). RMM provides a means to routinize and automate both the initial development and subsequent update process. It focuses on the design, development and constructions phases of the software development lifecycle. A graphical representation of RMM is in slide1.
RMDM vs. other data models
Data models like Data Flow Diagrams and Entity-Relationship models are useful abstractions in systems design, but the peculiarities of hypermedia, in particular the navigation aspect, require new models. A data model for a system details its internal structure but is of little value in modeling hypermedia applications. The Relationship Management Data Model (RMDM) provides a language for describing the information objects and the navigation mechanisms in hypermedia applications. This is the cornerstone of RMM. It provides a strong prescription for choosing the nodes and links in the hypermedia application, which would otherwise be unclear in other data models.
The artefacts that are used in RMDM are shown in slide 2. It uses the E-R symbols and RM design symbols, as well as access symbols which provide navigational properties.
Because entities may consist of a large number of attributes of different nature, it may be unrealistic to present all of the attributes of the entity instance at once. So attributes are grouped into slices, which are unique to hypermedia applications. For example, a college instructor entity with attributes name, age, research interest and biography may have a general slice containing name, age, a research interest slice and a biography slice. The biography slice will contain the name and biography and the research interest slice consists of the name and research interest. So each instructor entity will be presented by three slices. The user may choose which one to view depending on the application.
The links (access symbols) specify access between slices of an entity. Navigation across different entities is supported via indices, guided tours and groupings. Structural connections are drawn with solid lines, whereas dashed lines are used for associative relationships.
Slide 3 illustrates examples of a Relationship Management Design diagram. It portrays the typical relationship between instructors and courses at a faculty. Diagram (a) shows how conditional indexed guided tours implement the associative one-many relationships 'Teach' and 'Taught_by'. The use of conditional access symbols to provide access beyond that derived from associative relationships is shown in (b). The two groupings, 'Main Menu' and 'Instructor Submenu', implement a hierarchical menu-like access mechanism.
Benefits of RMM
The design of a WWW application can be succinctly represented with RMM diagrams so that designers, programmers and users have a clear understanding of the scope and structure of the application. Advantages of RMM are provided in slide 4.
References:
"RMM: A Methodology for Structured Hypermedia Design", T. Isakowitz, E.A. Stohr, P. Balasubramanium. Communications of the ACM, Vol. 38, No. 8, Aug. 1995, pp. 34--37.
"RMC: A Tool to Design WWW Applications", A. Diaz, T. Isakowitz, V. Maiorana, G. Gilabert. Proceedings of the Fourth International World Wide Web Conference, Dec. 1995.
"A Systematic Approach to Designing a WWW Application", V. Balasubramanium, B.M. Ma, J. Yoo. Communications of the ACM, Vol. 38, Aug. 1995, pp. 47--48.
"Hypermedia Design", S. Frasse, F. Garzotto, T. Isakowitz, J. Nanard, M. Nanard, eds., SpringerVerlag, Workshops in Computing Series, 1996, 252+x111 pages.