Presentation on theme: "The ANSI/SPARC Architecture of a Database Environment"— Presentation transcript:
1The ANSI/SPARC Architecture of a Database Environment Lecture 2
2Schema and instance database schema database instance the description of the database is called the database schema or intension;specified at the creation of the databasenot expected to change very oftendatabase instancethe raw data that populates a database at a particular moment in time is called a database instance of the extension of the database
14Application programs user developed provided by developers in a third generation languageprovide an embedded data sub-languageprovided by developersfourth generation languageexamples: query processors, statistical packages, reports/forms generators
15Database management system provides support fordata manipulation / definitiondata sub-languages (computationally incomplete)data integritysecurity controlrecovery servicesconcurrency facilitiesdata communicationaccessing the data dictionarywhy needed? applications’ automatic access to the DB
16People data administrator database administrator relevance and meaning of data; standards; policydatabase administratordesign, implementation and maintenance of the DBapplication programmersend user
17Summarythe three level ANSI/SPARC architecture of a database environmentthe components of a database environment
18Activity A2Which role within a database environment would you prefer to be in, if you were able to choose? Why? Which activities would you be interested in performing? How would you like to co-operate with the people performing the other roles?