Relational Model Introduction - E-Courses

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<strong>Relational</strong> Database Scheme and Instance <strong>Relational</strong> database scheme: D consist of a finite no. of relation schemes and a set I of integrity constraints. Integrity constraints: Necessary conditions to be satisfied by the data values in the relational instances so that the set of data values constitute a meaningful database • domain constraints • key constraints • referential integrity constraints Database instance: Collection of relational instances satisfying the integrity constraints. Prof P Sreenivasa Kumar Department of CS&E, IITM 6
Domain and Key Constraints • Domain Constraints: Attributes have associated domains Domain – set of atomic data values of a specific type. Constraint – stipulates that the actual values of an attribute in any tuple must belong to the declared domain. • Key Constraint: Relation scheme – associated keys Constraint – if K is supposed to be a key for scheme R, any relation instance r on R should not have two tuples that have identical values for attributes in K. Also, none of the key attributes can have null value. Prof P Sreenivasa Kumar Department of CS&E, IITM 7
Page 1 and 2: Introduction Relational Model Prop
Page 3 and 4: Relation Instance A finite set of
Page 5: Keys for a Relation (2/2) A relati
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 and 16: Example Relational Scheme student (
Page 17 and 18: Relational Algebra A set of operat
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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