18-06-2012, 12:54 PM
Object-Relational DBMSs
Object-Relational DBMSs.ppt (Size: 241 KB / Downloads: 73)
Introduction to O-R database systems
RDBMSs currently dominant database technology with estimated sales $50 billion with tools sales included, and growing rate possibly 25% per yr.
OODBMS market still small, with sales of $150 million in 1996 and a 3% market share in 1997.
Some expect OODBMS market to grow at over 50% per year, but unlikely to overtake RDBMS
Vendors of RDBMSs conscious of threat and promise of OODBMS.
Agree that RDBMSs not currently suited to advanced database apps,
Reject claim that extended RDBMSs will not provide sufficient functionality/be too slow to cope adequately with new complexity.
The first way: the “3-G Database System Manifesto”
1. A 3rd generation DBMS must have a rich type system.
2. Inheritance is a good idea.
3. Functions, including database procedures, methods… are a good idea.
4. DBMS assigns unique identifiers for records only if no user-defined PK
5. Rules (triggers, constraints) will become a major feature in future. They should not be associated with a specific function or collection.
6. all programmatic access to a database should be through a non-procedural, high-level access language.
7. Should be at least two ways to specify collections, one using enumeration of members and one using query language.
8. Updateable views are essential.
9. Performance indicators should not appear in data models
10. For better or worse, SQL is “intergalactic dataspeak”.