The Entity-Relationship Model

1. The Entity-Relationship Model ALA/ALCTS Preconference RDA, FRBR, and FRAD: Making the Connection July 10, 2009 Robert L. Maxwell

2. What is Entity-Relationship (ER)? • A database model introduced in the1970s • An alternative to the previous flat-file model • E.g., MARC has a flat-file structure • ER divides data into defined entities • Entities are linked by defined relationships • Entities and relationships may have specified attributes in a given model

3. Entities • An entity is a general category within a data universe that can be distinctly identified. For example: • Employees • Customers • Objects • Events

4. Entity sets • An entity set is a group of specific instances of a defined entity • E.g., members of the entity set “work” might contain • Tom Sawyer • Gone with the Wind • Ulysses • Set members are often referred to as “entities” but remember that they are actually specific instances of an entity

5. Groupings within entities • Defined entities may have subsets • For example, if we define a “person” entity we might have the following subsets in our database model • Poets • Parents • Editors • Children • Composers

6. Roles • As an alternative to defining subsets, a database model might instead define roles • A role is a function that an instance of an entity performs in a relationship • For example, there may be a relationship between a person and a work. If the model specifies roles, a role such as “composer” or “poet” might be assigned to this particular relationship.

7. Relationships • An association between two or more entities • For example, there may be a “mother-daughter” relationship between two persons in a genealogical database • In a bibliographic database, there may be • “Earlier-later” relationship between two corporate bodies • “Broader-narrower” relationship between two concepts • “Creator” relationship between a person and a work

8. Relationship sets • A relationship set is a group of specific instances of a defined relationship • Database design could include provision for queries retrieving all instances of a particular relationship set. • For example, if a “composed by” relationship is defined, all instances of this relationship could be retrieved by users of a music library to find all the composers in the collection.

9. Attributes • ER database models define attributes for entities and relationships • Attributes are general characteristics that uniquely identify entities or relationships • For example, an attribute of “person” in FRBR is “name” because a name is one of the things that distinguishes persons • Different database models define entities, relationships, and attributes differently

10. ER Diagramming • Traditional ER diagramming: • Instances of entities are represented by rectangles • Instances of relationships are represented by diamonds • Instances of attributes are represented by ovals • Next slide gives a simplified example from the FRBR model; the following slide shows the same in FRBR diagramming

11. Title of Manifestation Name Statement of Responsibility Birth/Death Dates Title Edition designation Manifestation Person produced by Corporate Body Date Produced Name Place Produced Place Date(s) ER Diagramming

12. Manifestation is produced by Person Corporate Body FRBR Diagramming

13. FRBR Entities Group 1 The products of intellectual or artistic endeavor Work Expression Manifestation Item

14. FRBR Entities Group 2 Entities that can produce or own Group 1 entities Person Corporate body Family [added with FRAD]

15. FRBR Entities Group 3 Entities that can serve as subjects Concept Object Event Place Plus any entity from Groups 1 or 2

16. Database Exercise • Included in your packet is a “database” worked out on paper as well as blank forms • Each sheet of paper represents one instance of a FRBR entity, with spaces for giving attribute data and spaces for specifying relationship links with other entity instances • Starting with the “seed” database, we will add new instances of FRBR entities or relationships as needed to add materials to our library

17. Works in the Database

18. Concept: Science fiction, American (C-011) has a literary form Person: Orson Scott Card (P-001) created by Work: Speaker for the dead (W-004) Work: Ender’s game (Short story) (W-002) has a sequel derived from Work: Ender’s game (Novel) (W-001) Work: Ender’s game (Graphic novel) (W-003) derived from has a subject Concept: Space warfare—Fiction (C-006) Related works, persons, and concepts

19. Person: Orson Scott Card (P-001) Person: M.K. Stuyter (P-003) created by Work: Ender’s game (Novel) (W-001) translated by has an expression Expression: Dutch, 1989 (E-003) has a manifestation Expression: English, 1985 (E-001) has a manifestation Manifestation: Amsterdam: Muelenhoff SF, 1989 (M-005) Manifestation: Amsterdam: Muelenhoff SF, 1994 (M-006) Manifestation: New York: Tor, 1985 (M-001) Manifestation: London: Century, 1985 (M-002) Manifestation: New York: Tor, 1986 (M-003) Related works, expressions, manifestations

20. Work: Ender’s game (Novel) (W-001) Expression: English, 1985 (E-001) created by has an expression has a manifestation Manifestation: New York: Tor, 1985 (M-001) Person: Orson Scott Card (P-001) has an item signed by Item: 31197229045536 Americana PZ4.C178 E52 1985 (I-001) Item: 31197229045528 Main Library PZ4.C178 E52 1985 (I-002) owned by Corporate body: Harold B. Lee Library (CB-001) Related works, expressions, manifestations, items

21. Adding to the Database Unabridged text recorded in 2001 by Stefan Rudnicki produced in compact disc and audiocassette

22. Information about the new Expression • ID = E-005 • Form: Spoken word • Date of the recording: 2001 • Language: English • Content type: Spoken word • Narrator: Stefan Rudnicki [and others] • Other information: This is an unabridged recording from the TOR paperback edition (already in the database)

23. Work: Ender’s game (Novel) (W-001) Expression: English, 1985 (text on paper) (E-001) created by has an expression New relationship Person: Orson Scott Card (P-001) Expression: English, 1985 (audiobook) (E-005) New entity has a form New relationship Concept: Audiobooks (C-012) Adding the new expression

24. Information about the new Person • ID = P-004 • Preferred name: Stefan Rudnicki • Date of birth: 1 Jan. 1945 • His language: English • His profession: Actor, narrator

25. Work: Ender’s game (Novel) (W-001) Expression: English, 1985 (text on paper) (E-001) created by has an expression Person: Orson Scott Card (P-001) Expression: English, 1985 (audiobook) (E-005) has a form performed by New relationship Concept: Audiobooks (C-012) New entity Person: Stefan Rudnicki (P-004) Adding new person entity

26. Information about the CD Manifestation • ID = M-007 • ISBN 1574535366 • Title proper: Ender’s game • S of R relating to title proper: Orson Scott Card • Other S of R: performed by Stefan Rudnicki • Edition: Author’s definitive edition • Place of publication: San Bruno, CA • Publisher: Fantastic Audio • Date of publication: 2002 • Carrier type: audio disc • Extent: 10 sound discs • Dimensions: 12 cm

27. Work: Ender’s game (Novel) (W-001) Expression: English, 1985 (text on paper) (E-001) created by has an expression Concept: Audiobooks (C-012) has a form Person: Orson Scott Card (P-001) Expression: English, 1985 (audiobook) (E-005) performed by has a manifestation New relationship Person: Stefan Rudnicki (P-004) Manifestation: Fantastic Adio, 2002 (compact disc) (M-007) New entity has a form New relationship Concept: Compact discs (C-013) Adding the CD manifestation

28. Information about the Cassette Manifestation • ID = M-008 • ISBN 1574535145 • Title proper: Ender’s game • S of R relating to title proper: Orson Scott Card • Other S of R: performed by various artists • Edition: Author’s definitive edition • Place of publication: San Bruno, CA • Publisher: Fantastic Audio • Date of publication: 2001 • Carrier type: audiocassette • Extent: 8 audiocassettes • Dimensions: 10 x 7 cm, 4mm tape

29. Work: Ender’s game (Novel) (W-001) Expression: English, 1985 (text on paper) (E-001) created by has an expression Concept: Audiobooks (C-012) has a form Person: Orson Scott Card (P-001) Manifestation: Fantastic Audio, 2001 (audiocassette) (M-008) New entity Expression: English, 1985 (audiobook) (E-005) performed by New relationship has a manifestation New relationship Person: Stefan Rudnicki (P-004) has a form Manifestation: Fantastic Audio, 2002 (compact disc) (M-007) Concept: Audiocassettes (C-014) has a form Concept: Compact discs (C-013) Adding cassette manifestation

30. Item records • Compact disc: • ID = I-007 • Barcode: 31197223328466 • Call number: Americana PZ 4 .C178 E52 2002b • Cassette: • ID = I-008 • Barcode: 31197223329258 • Call number: Americana PZ 4 .C178 E52 2001

31. Work: Ender’s game (Novel) (W-001) Expression: English, 1985 (text on paper) (E-001) created by has an expression Person: Orson Scott Card (P-001) Manifestation: Fantastic Audio, 2001 (audiocassette) (M-008) Expression: English, 1985 (audiobook) (E-005) performed by New relationship has an item has a manifestation Person: Stefan Rudnicki (P-004) Item:31197223329258 Americana PZ 4 .C178 E52 2001(I-008) New entity Manifestation: Fantastic Audio, 2002 (compact disc) (M-007) New entity Item: 31197223328466 Americana PZ 4 .C178 E52 2002b (I-007) has an item New relationship owned by New relationship Corporate body: Harold B. Lee Library (CB-001) Adding new entities

32. Relationship links to think about here • Work/Expression/Manifestation/Item links • Narrator/narrated by • Genre/form • Owner

33. ER vs. MARC • Advantages of ER? • Disadvantages?

34. Questions? robert_maxwell@byu.edu