Lecture 3 - Relational Model

# Lecture 3 - Relational Model - Introduction to Database...

This preview shows pages 1–12. Sign up to view the full content.

IS 230 Lecture 3 – The Relational Model Slide 1 Lecture 3 The Relational Model Introduction to Database Systems IS 230 This is the instructor’s notes and student has to read the textbook for complete material. Dr. Jawad Berri

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
IS 230 Lecture 3 – The Relational Model Slide 2 Lecture Outline The Relational Data Model and Relational Database Constraints Relational Model Constraints and Relational Database Schemas Update Operations, Transactions, and Dealing with Constraint Violations
IS 230 Lecture 3 – The Relational Model Slide 3 The Relational Data Model and Relational Database Constraints Relational model First commercial implementations available in early 1980s Has been implemented in a large number of commercial system Hierarchical and network models Preceded the relational model

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
IS 230 Lecture 3 – The Relational Model Slide 4 Relational Model Concepts Represents data as a collection of relations Table of values Row Represents a collection of related data values Fact that typically corresponds to a real-world entity or relationship Tuple Table name and column names Interpret the meaning of the values in each row attribute
IS 230 Lecture 3 – The Relational Model Slide 5 Relational Model Concepts (cont’d.)

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
IS 230 Lecture 3 – The Relational Model Slide 6 Domains, Attributes, Tuples, and Relations Domain D Set of atomic values Atomic Each value indivisible Specifying a domain Data type specified for each domain
IS 230 Lecture 3 – The Relational Model Slide 7 Domains, Attributes, Tuples, and Relations (cont’d.) Relation schema R Denoted by R ( A 1 , A 2 , ..., A n ) Made up of a relation name R and a list of attributes, A 1 , A 2 , ..., A n Attribute A i Name of a role played by some domain D in the relation schema R Degree (or arity ) of a relation Number of attributes n of its relation schema

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
IS 230 Lecture 3 – The Relational Model Slide 8 Domains, Attributes, Tuples, and Relations (cont’d.) Relation (or relation state ) Set of n -tuples r = { t 1 , t 2 , ..., t m } Each n -tuple t Ordered list of n values t =<v 1 , v 2 , ..., v n > Each value v i , 1 ≤ i ≤ n , is an element of dom( A i ) or is a special NULL value
IS 230 Lecture 3 – The Relational Model Slide 9 Domains, Attributes, Tuples, and Relations (cont’d.) Relation (or relation state) r ( R ) Mathematical relation of degree n on the domains dom( A 1 ), dom( A 2 ), ..., dom( A n ) Subset of the Cartesian product of the domains that define R: r ( R ) (dom (A 1 ) × dom( A 2 ) × ... × dom( A n ))

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
IS 230 Lecture 3 – The Relational Model Slide 10 Domains, Attributes, Tuples, and Relations (cont’d.) Cardinality Total number of values in domain Current relation state Relation state at a given time Reflects only the valid tuples that represent a particular state of the real world Attribute names Indicate different roles , or interpretations, for the domain
IS 230 Lecture 3 – The Relational Model Slide 11 Characteristics of Relations

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern