Chapter 22:Object-Based Databases Complex Data Types and Object Orientation Structured Data Types and Inheritance in SQL Table Inheritance Array and Multiset Types in SQL Object Identity and Reference Types in SQL Implementing O-R Features Persistent Programming Languages Comparison of Object-Oriented and Object-Relational Databases Database System Concepts-6th Edition 22.2 ©Silberschat乜，Korth and Sudarshan
Database System Concepts - 6 22.2 ©Silberschatz, Korth and Sudarshan th Edition Chapter 22: Object-Based Databases Complex Data Types and Object Orientation Structured Data Types and Inheritance in SQL Table Inheritance Array and Multiset Types in SQL Object Identity and Reference Types in SQL Implementing O-R Features Persistent Programming Languages Comparison of Object-Oriented and Object-Relational Databases
Object-Relational Data Models Extend the relational data model by including object orientation and constructs to deal with added data types. Allow attributes of tuples to have complex types,including non-atomic values such as nested relations. Preserve relational foundations,in particular the declarative access to data,while extending modeling power. Upward compatibility with existing relational languages. Database System Concepts-6th Edition 22.3 @Silberschatz,Korth and Sudarshan
Database System Concepts - 6 22.3 ©Silberschatz, Korth and Sudarshan th Edition Object-Relational Data Models Extend the relational data model by including object orientation and constructs to deal with added data types. Allow attributes of tuples to have complex types, including non-atomic values such as nested relations. Preserve relational foundations, in particular the declarative access to data, while extending modeling power. Upward compatibility with existing relational languages
Complex Data Types Motivation: Permit non-atomic domains (atomic indivisible) Example of non-atomic domain:set of integers,or set of tuples Allows more intuitive modeling for applications with complex data Intuitive definition: allow relations whenever we allow atomic(scalar)values -relations within relations Retains mathematical foundation of relational model Violates first normal form. Database System Concepts-6th Edition 22.4 ©Silberschat乜，Korth and Sudarshan
Database System Concepts - 6 22.4 ©Silberschatz, Korth and Sudarshan th Edition Complex Data Types Motivation: Permit non-atomic domains (atomic indivisible) Example of non-atomic domain: set of integers,or set of tuples Allows more intuitive modeling for applications with complex data Intuitive definition: allow relations whenever we allow atomic (scalar) values — relations within relations Retains mathematical foundation of relational model Violates first normal form
Example of a Nested Relation Example:library information system Each book has title, a list(array)of authors, Publisher,with subfields name and branch,and a set of keywords Non-1NF relation books title author_array publisher keyword_set (name,branch) Compilers [Smith,Jones] (McGraw-Hill,New York) [parsing,analysis} Networks [Jones,Frick] (Oxford,London) [Internet,Web Database System Concepts-6th Edition 22.5 ©Silberschat乜，Korth and Sudarshan
Database System Concepts - 6 22.5 ©Silberschatz, Korth and Sudarshan th Edition Example of a Nested Relation Example: library information system Each book has title, a list (array) of authors, Publisher, with subfields name and branch, and a set of keywords Non-1NF relation books
4NF Decomposition of Nested Relation title author position Suppose for simplicity that title uniquely identifies a Compilers Smith 1 book Compilers Jones 2 Networks Jones 1 In real world ISBN is a Networks Frick 2 unique identifier authors Decompose books into 4NF using the schemas: title keyword (title,author,position Compilers parsing (title,keyword Compilers analysis (title,pub-name,pub- Networks Internet branch Networks Web 4NF design requires users keywords to include joins in their queries. title pub_name pub_branch Compilers McGraw-Hill New York Networks Oxford London books4 Database System Concepts-6th Edition 22.6 ©Silberschat乜，Korth and Sudarshan
Database System Concepts - 6 22.6 ©Silberschatz, Korth and Sudarshan th Edition 4NF Decomposition of Nested Relation Suppose for simplicity that title uniquely identifies a book In real world ISBN is a unique identifier Decompose books into 4NF using the schemas: (title, author, position ) (title, keyword ) (title, pub-name, pubbranch ) 4NF design requires users to include joins in their queries