August 2009
Intermediate to advanced
893 pages
26h 48m
English
Content preview from Database Systems: Concepts, Design and Applications
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
Start your free trial
2.3. Three-level ANSI-SPARC Data Base Architecture
For the first time in 1971, Database Task Group (DBTG) appointed by the Conference on Data Systems and Languages (CODASYL), produced a proposal for general architecture for database systems. The DBTG proposed a two-tier architecture as shown in Fig. 2.1 (a) with a system view called the schema and user views called subschemas. In 1975, ANSI-SPARC (American National Standards Institute – Standards Planning and Requirements Committee) produced a three-tier architecture with a system catalog. The architecture of most commercial DBMSs available today is based to some extent on ANSI-SPARC proposal.
ANSI-SPARC three-tier database architecture is shown in Fig. 2.6. It consists of following three levels: ...