Modeling, Metadata, and
XML
By
Ken North
The two previous columns in this space dealt with a cookbook approach to
database development. This month I hope to provide enough information for
you to decide whether to learn Object-Role Modeling (ORM), the Unified Modeling
Language (UML) and the eXtensible Markup Language (XML). UML and ORM are obviously
modeling technologies, but where does XML fit into the picture? Why did I
include XML with two obvious modeling technologies? XML is more than a document
markup language -- it's a solution for content modeling and creating standards
for content.
Developers have been building information systems or information engineering
models for several decades. The first generations of modeling tools and technologies
centered on process and data modeling. System-level flow charts are early
examples of process modeling, whereas Natural Language Information
Analysis Method (NIAM) and data flow diagrams (DFD) were early data-modeling
techniques. More recent modeling technologies support object-oriented analysis
and design (OOAD). Data modeling is the process of creating models
when designing databases, typically following a progression from conceptual
model to logical model to physical schema. Most data-modeling products support
entity-relationship diagrams (ERD), object-role modeling (ORM), and Integration
Definition for Information Modeling (IDEF1X) models.
