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Database Systems: Lecture 4 - Nguyen Thanh Tung

Database Systems: Lecture 4 - Relational Data Model and ER-/EER-to-Relational Mapping provides about Relational Data Model, ER-/EER-to-Relational Mapping, Relational Integrity Constraints, Update Operations on Relations, Main Phases of Database Design. | Relational Data Model and ER-/EER-to-Relational Mapping Outline Relational Data Model ER-/EER-to-Relational Mapping Reading Suggestion: [1]: Chapters 5, 7, 12 [2]: Chapters 15, 16 Relational Data Model Basic Concepts: relational data model, relation schema, domain, tuple, cardinality & degree, database schema, etc. Relational Integrity Constraints key, primary key & foreign key entity integrity constraint referential integrity Update Operations on Relations Basic Concepts The relational model of data is based on the concept of a relation A relation is a mathematical concept based on the ideas of sets The model was first proposed by Dr. E.F. Codd of IBM in 1970 in the following paper: "A Relational Model for Large Shared Data Banks," Communications of the ACM, June 1970 Basic Concepts Relational data model: represents a database in the form of relations - 2-dimensional table with rows and columns of data. A database may contain one or more such tables. A relation schema | Relational Data Model and ER-/EER-to-Relational Mapping Outline Relational Data Model ER-/EER-to-Relational Mapping Reading Suggestion: [1]: Chapters 5, 7, 12 [2]: Chapters 15, 16 Relational Data Model Basic Concepts: relational data model, relation schema, domain, tuple, cardinality & degree, database schema, etc. Relational Integrity Constraints key, primary key & foreign key entity integrity constraint referential integrity Update Operations on Relations Basic Concepts The relational model of data is based on the concept of a relation A relation is a mathematical concept based on the ideas of sets The model was first proposed by Dr. E.F. Codd of IBM in 1970 in the following paper: "A Relational Model for Large Shared Data Banks," Communications of the ACM, June 1970 Basic Concepts Relational data model: represents a database in the form of relations - 2-dimensional table with rows and columns of data. A database may contain one or more such tables. A relation schema is used to describe a relation Relation schema: R(A1, A2, , An) is made up of a relation name R and a list of attributes A1, A2, . . ., An. Each attribute Ai is the name of a role played by some domain D in the relation schema R. R is called the name of this relation The degree of a relation is the number of attributes n of its relation schema. Domain D: D is called the domain of Ai and is denoted by dom(Ai). It is a set of atomic values and a set of integrity constraints STUDENT(Name, SSN, HomePhone, Address, OfficePhone, Age, GPA) Degree = ?? dom(GPA) = ?? Basic Concepts Tuple: row/record in table Cardinality: number of tuples in a table Database schema S = {R1, R2, , Rm} Basic Concepts A relation (or relation state, relation instance) r of the relation schema R(A1, A2, . . ., An), also denoted by r(R), is a set of n-tuples r = {t1, t2, . . ., tm}. Each n-tuple t is an ordered list of n values t = , where each value vi, i=1n, is an element of dom(Ai) or