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Object-Oriented Data Bases - Coggle Diagram
Object-Oriented Data Bases
Motivation
the need to integrate complex data with simple data drives
the need to store large amounts of complex data
Architectures
Large Objects and External Software
simple to implement and is universal
All kinds of complex data
serious performance drawbacks
no optimization is possible
Object Database Middleware
can suffer performance problems
lack of integration with a DBMS
Combining data suffers the same performance problems
Object-Oriented Database Management Systems
proposed an object definition language
proposed object query language
provided ad hoc query
query optimization
efficient transaction suppor
Specialized Media Servers
complex data reside outside of a DBMS
good performance for specific kinds of complex data
the range of operations may be limited
DBMS is not aware of complex data
Object Relational Database Management Systems for User-Defined Types
support user-defined types
good integration of complex data
Inheritance and polymorphism
third-party data types can be subject to viruses
Object-oriented methodologies concept
an object is an instance of an object type;
an operation is a set of actions to be performed on an object;
an object type is a concept or thing about which data is to be stored, and a set of operations is to be defined;
method specifies the way an operation is to be performed;
encapsulation is the packaging of data structure and operations, typically into a class.
inheritance: a subclass may inherit properties (structure or operations from a subclass). Also, a class may be comprised of several component classes;
polymorphism is the phenomenon where a given object or operation may take on a different form, depending on the context of usage;
objects communicate by sending messages to each other. These messages are managed via events; an object therefore responds to events.