The Orion 2.0 system provides built-in support for uncertainty at the database level. By extending the
query processing engine of PostgreSQL, Orion natively manages uncertain data modeled as arbitrary joint probability
distributions. Orion 2.0 is a complete redesign and rewrite
of its predecessor U-DBMS , and includes the following
new and innovative contributions :
- An integrated implementation (within PostgreSQL) of
the data model in , which is consistent
with Possible Worlds Semantics (PWS) and supports
both continuous and discrete uncertainty.
- Efficient access methods for querying uncertain data,
including three index structures based on R-trees, signature trees, and inverted indexes [6,16].
- Improved query optimization, join algorithms, and selectivity estimation by
gathering and exploiting additional statistics over probabilistic data types [5,17].
- Integration with for graphical visualization of
and statistical inference over uncertain data .
The system architecture of Orion 2.0 is given in Figure 1. A detailed explanation of different
components in the architecture is given in Section 3.
Orion 2.0 Architecture