Review Session Quiz 1 · 2017. 10. 15. · Entity Relationship Diagrams Basic Terms and Concepts 1.Entities 2.Relationships Design Constraints 1.Entity Sets vs Attributes 2.Entity
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ReviewSessionQuiz1
DifferentTopicsCoveredatthisPoint
• RelationalAlgebra• RelationalModel• Entity-RelationshipModel• TupleRelationalCalculus(Notontest)• Sql 1• Sql 2• Constraints
RelationalAlgebra
BasicOperators1.Select(σ)2.Project(π)3.Union(∪)4.Setdifference(–)5.Cartesianproduct(X)6.Rename(ρ)
AdvancedOperators1.NaturalJoin(⨝)2.Division(÷)3.Aggregation(g)4.OuterJoins(⟕⟗⟖)
ExampleQuestion
ExampleQuestion
ExampleQuestion2
QuestionsonRelationalAlgebra?
BasicOperators1.Select(σ)2.Project(π)3.Union(∪)4.Setdifference(–)5.Cartesianproduct(X)6.Rename(ρ)
AdvancedOperators1.NaturalJoin(⨝)2.Division(÷)3.Aggregation(g)4.OuterJoins(⟕⟗⟖)
EntityRelationshipDiagrams
BasicTermsandConcepts1. Entities2. RelationshipsDesignConstraints1. EntitySetsvsAttributes2. EntitySetsvsRelationshipSets3. RelationshipCardinalities4. WeakEntitySets5. Inheritance
Typesofkeys1.CandidateKeys2.SuperKeys3.PrimaryKeys
TranslatingERDiagramsToRelationalSets
QuestionsonTupleRelationalCalculus?
FormulaSetup:1. Queryhastheform:{T|p(T)}2. AnsweristhesetofalltuplesT
forwhichtheformulap(T)evaluatestotrue.
AvailableOperations1. ¬p,p∨ q,p∧q
1. PandQareformulas
2. ∃R(p(R))1. Risatuplevariable
3. ∀R(p(R))1. Risatuplevariable
SQL
• BasicStructure
• OtherIdeas• DistinctClause• NaturalJoin• RenameOperator• AggregateFunctions
• GroupBy• NestedSubQueries
ExampleQuestion
ExampleQuestion
ExampleQuestion
ExampleQuestionCont.
• Breaktheproblemupintosubparts
Constraints
IntegrityConstraints1.PrimaryKey2.AttributeConstraint3.ReferentialIntegrityConstraint4.GlobalConstraints
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