About (FRBR) Data Modeling: Conceptual Data Modeling In Cultural Heritage Institutions Ronald J. Murray Library of Congress Washington DC USA Workshop on FRBR in the European Library Lisboa, Portugal October 9, 2008
Data Modeling in General • Definitions • About data modeling • Data models as “Paper Tools” • Data modeling examples • What to do now
Data Modeling in General • Definitions – Conceptual Data Model: A description of a portion of an enterprise in terms of the fundamental things of interest to it. They are fundamental in that most things seen by business owners are examples of these. – Logical Data Model: The organization of data for use with a particular data management technology. For relational databases, these are tables and columns; for object-oriented databases, object classes and attributes. • The MARC bibliographic standard specifies a logical data model that uses tags and delimiters to structure bibliographic data. In practice, the bibliographic conceptual data model is tangled up in the logical data model – Physical Data Model: The organization of data used to place it on specific storage media. This level refers to “tablespaces” and “cylinders.” – General Definition : The specification of a final conceptual data model and an initial logical data model that together meet business requirements, prior to any performance tuning.
About Data Modeling • Why a Data Model is Important • What Makes a Good Data Model? • What Makes a Good Data Modeler? • What is the Description/Design Question?
About Data Modeling • Why a Data Model is Important – Leverage : Small changes in the data model have major effects on the system design and final implementation – Conciseness : The relatively compact data model takes less time to review that the functional specification, and in-depth understanding easier to achieve – Data Quality : Data quality problems are often traceable to inconsistent data definition, interpretation, and enforcement mechanisms
About Data Modeling • Why a Data Model is Important – It serves as a necessary complement to a function and process model • The database system design and implementation process described here can involve three types of modeling • A data model describes the information an enterprise must have on hand to execute its functions • A function model describes what an enterprise must do • A process model describes how an enterprise must do it. – Function and process models are regularly combined during the database system design process – It can function as a “Paper Tool” in service of theoretical and practical ends
About Data Modeling • What Makes a Good Data Model? – Completeness – Nonredundancy – Enforcement of Business Rules – Data Reusability – Stability & Flexibility – Elegance – Communication – Integration
About Data Modeling • What is the Description/Design Question? – Is data modeling best characterized as a descriptive activity, the objective of which is to document some aspect of the real world ? – Is data modeling best characterized as a design activity, the objective of which is to create data structures to meet a set of requirements ? – Does the history of the development and implementation of the FRBR model reflect aspects of this controversy? Portions quoted from Simsion, Graeme (2007). Data Modeling: Theory and Practice. p.3.
About Data Modeling • How is the Description/Design Issue Manifest? – Explicit arguments among practitioners and academics, as to whether the description or design paradigm was correct. – Clashes between practitioners who subscribed to the descriptive paradigm, but had produced different models that were difficult to reconcile. – Disagreement over the appropriateness of data modelers introducing new concepts and terminology rather than simply documenting an established view of business entities. Quoted from Simsion, Graeme (2007). Data Modeling: Theory and Practice. p.10.
About Data Modeling • How is the Description/Design Issue Manifest (cont.) ? – Difficulty in teaching data modeling using texts and teaching materials which treated it as a descriptive process. – Experienced data modeling practitioners struggling to develop models, and observing that data modeling in practice was much more difficult than it should be if it was essentially concerned with describing data requirements. – Antipathy towards data modelers, who were frequently seen as pursuing an ideal description of reality rather than contributing in the most productive way to an information system design. Quoted from Simsion, Graeme (2007). Data Modeling: Theory and Practice. p.10.
About Data Modeling • Description/Design Issue Findings – The description/design issue is considered an important one by data modeling practitioners • Evenly divided on opinion – Data modeling extends into the implementation- oriented Logical Data Model stage – Database design methods used in practice support the design paradigm – Data modeling product variation supports a design paradigm with many possible models, plus there are effects of training and personal modeling stylees From Simsion, Graeme (2007). Data Modeling: Theory and Practice. p.326-3xxx.
About Data Modeling • Description/Design Issue Implications for FRBR – Expect FRBR data modeling efforts to encounter similar issues – In compensation, develop an approach that allows theory to guide (but not dictate) FRBR design efforts • Design data structures that meet requirements • Test data models - as Paper Tools - in theory-driven scenarios, and allow each to mutually inform and creatively correct one another – Employ multiple sources for theory – Employ data modeling conventions and patterns From Simsion, Graeme (2007). Data Modeling: Theory and Practice. p.326-3xxx.
FRBR Data Modeling Using Paper Tools • What are paper tools? • Who uses them? • Why should we use a paper tool for reasoning about bibliographic relationships? • How do we use them?
The Data Model As Paper Tool • Paper Tool † - A collection of symbolic elements (diagrams, characters, etc.), whose construction and manipulation follow rules and constraints of one or more guiding theories – Paper tool manipulation permits rapid, flexible, and creative exploration of phenomena of interest – Paper tool/user dialogs can generate unprecedented manipulations, and change the interests and goals of a modeling effort – One can reason theoretically as well as practically with a paper tool • Examples abound in the Sciences • Can use for FRBR theory formation and testing • Clears the way for specification of data structures that meet user requirements † Klein, Ursula (2001) ‘Paper Tools in Experimental Cultures’, Studies in History and Philosophy of Science 32: 265–302.
A Paper Tool For Modeling Physics Feynman Diagrams & Diagramming Rules † † http://www2.slac.stanford.edu/vvc/theory/feynman.html. Kaiser, David. Drawing Theories Apart: The Dispersion of Feynman Diagrams in Postwar Physics. Chicago, IL: University of Chicago Press. 2005.
Data Modeling With Paper Tools • Why use a paper tool for reasoning about bibliographic (or any other) relationships? – Efficient presentation of entities, attributes, relationships, and business rules – Can validate obvious and non-obvious aspects of the data model by creating and validating simple and complex model diagrams • Diagram construction can be heavily constrained by (FRBR) theory • Example – Modeling a collection of resources and resource descriptions – Simple to complex resource structuring – Addition of resource relationships – “Factoring out” hierarchical structures from a more complex whole
FRBR Paper Tool Example Work Expression Manifestation Item
FRBR Paper Tool Example The basic diagram element represents a resource and the overall description of that resource Work Expression Manifestation Item
FRBR Paper Tool Example A black-filled circle means that a resource and a resource description are both present. A clear circle means that no resource is present Work Expression Manifestation Item
FRBR Paper Tool Example Work Expression The color squares designate Manifestation different descriptions of the Item resource. In this case, they reflect FRBR rules for resource description.
FRBR Paper Tool Example Work Expression Connections between descriptions Manifestation are made according to the rules for Item the point of view being represented.
FRBR Paper Tool Example Work Expression Squares placed next to one another Manifestation are linked together by the Item appropriate relationship. No lines are visible.
FRBR Paper Tool Example Work Expression If a color square is solid, that means Manifestation that a full resource description is Item present.
FRBR Paper Tool Example Work Expression If a color square is hollow, that Manifestation means that this description points to Item one or more descriptions of the same type . It acts as a container .
FRBR Paper Tool Example A container description must be linked to one or more descriptions of the same Type . (This is a Business Rule at work.) In this example, an Item (acting as a container) is composed of two other Items . Work Expression Manifestation Item Has Part Has Part
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