Advantages of ORDBMS
- Extend
the relational data model by including object orientation and constructs
and constructs to deal With added data types.
- Allow
attributes of tuples to have complex types, including non-atomic values
such as nested relations.
- Preserve
relational foundations, in particular the declarative access to data,
while extending modelling power.
- Upward compatibility with existing relational languages.
Disadvantages of ORDBMS
- Poor
representation of 'real world' conceptual model — usually the relational
schema does not correspond to real world entities.
- Difficult
to change schema without affecting the applications; e.g., Y2K.
- Semantic
overloading.
- Poor
support for integrity and business rules.
- Fixed
number of attributes and all attribute values must be atomic.
- Limited
operations.
- Difficult
to handle recursive queries.
- Impedance
mismatch (when SQL is embedded in PLs).
- Poor
navigational access.
- Short-lived
transactions (strict locking and recovery mechanisms).
