Features of Semi-Structured Data Models ■Arrays Widely used for scientific and monitoring applications E.g.,readings taken at regular intervals can be represented as array of values instead of(time,value)pairs ■[5,8,9,11]instead of{(1,5),(2,8),(3,9),(4,11)} Multi-valued attribute types Modeled using non first-normal-form(NFNF)data model Supported by most database systems today Array database:a database that provides specialized support for arrays E.g.,compressed storage,query language extensions etc Oracle GeoRaster,PostGIS,SciDB,etc Database System Concepts-7th Edition 8.5 ©Silberscha乜，Korth and SudarshanDatabase System Concepts - 7 8.5 ©Silberschatz, Korth and Sudarshan th Edition Features of Semi-Structured Data Models ▪ Arrays • Widely used for scientific and monitoring applications • E.g., readings taken at regular intervals can be represented as array of values instead of (time, value) pairs ▪ [5, 8, 9, 11] instead of {(1,5), (2, 8), (3, 9), (4, 11)} ▪ Multi-valued attribute types • Modeled using non first-normal-form (NFNF) data model • Supported by most database systems today ▪ Array database: a database that provides specialized support for arrays • E.g., compressed storage, query language extensions etc • Oracle GeoRaster, PostGIS, SciDB, etc