Relational Model Introduction - E-Courses

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Example <strong>Relational</strong> Scheme with RIC’s shown student (rollNo, name, degree, year, sex, deptNo, advisor) department (deptId, name, hod, phone) professor (empId, name, sex, startYear, deptNo, phone) course (courseId, cname, credits, deptNo) enrollment (rollNo, courseId, sem, year, grade) teaching (empId, courseId, sem, year, classRoom) preRequisite (preReqCourse, courseID) Prof P Sreenivasa Kumar Department of CS&E, IITM 16
<strong>Relational</strong> Algebra A set of operators (unary & binary) that take relation instances as arguments and return new relations. Gives a procedural method of specifying a retrieval query. Forms the core component of a relational query engine. SQL queries are internally translated into RA expressions. Provides a framework for query optimization. RA operations: select (σ), project (π), cross product (×), union (⋃), intersection (∩), difference (−), join ( ⋈ ) Prof P Sreenivasa Kumar Department of CS&E, IITM 17
Page 1 and 2: Introduction Relational Model Prop
Page 3 and 4: Relation Instance A finite set of
Page 5 and 6: Keys for a Relation (2/2) A relati
Page 7 and 8: Domain and Key Constraints • Doma
Page 9 and 10: Foreign Key - Examples(1/2) Foreign
Page 11 and 12: Referential Integrity Constraint (R
Page 13 and 14: Example Relational Scheme student (
Page 15: Example Relational Scheme student (
Page 19 and 20: Selection Condition • Select cond
Page 21 and 22: The project Operator Unary operato
Page 23 and 24: Size of project expression result
Page 25 and 26: Set Operations r 1 - relation with
Page 27 and 28: Example Query using cross product
Page 29 and 30: Theta join • Let r 1 - relation w
Page 31 and 32: Examples For each department, find
Page 33 and 34: Examples - Equi-join Find courses o
Page 35 and 36: Division operator The necessary co
Page 37 and 38: Query using division operation Find
Page 39 and 40: Complete Set of Operators • Are a
Page 41 and 42: More Example Queries Obtain the dep
Page 43 and 44: Outer Join Operation (2/2) Left out
Page 45 and 46: Left outer join temp ← (student a
Page 47 and 48: Full outer join temp ← (student a
Page 49 and 50: Relational representation of strong
Page 51 and 52: Example CourseID Name Credits Corre
Page 53 and 54: Handling Binary 1:1 relationship L
Page 55 and 56: Handling 1:N Relationship Let S be
Page 57 and 58: Handling M:N relationship Make a s
Page 59: Handling Recursive relationships M

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