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Object-Oriented Databases - Coggle Diagram
Object-Oriented Databases
Object-oriented methodologies
advantages
encapsulation
polymorphism
complexity
code reusability
preferable for scenarios
CAD systems
Multimedia systems
Geographic information systems
Document storage and retrieval systems
concepts
object type
data is to be stored
object
instance of an object type
operation
set of actions
method
way an operation is to be performed
encapsulation
packaging of data structure and operations
inheritance
subclass may inherit properties
polymorphism
object or operation may take on a different form
objects communicate by sending messages to each other
earliest approach
use large objects with external software
Complex data are stored in a column
as a binary
as a text
large objects are stored separately
limitations
performance drawbacks
optimization is possible
cannot be filtered of large objects
No indexes can be used to select records
additional disk accesses may be necessary
Specialized Media Servers
complex data reside outside of a DBMS
using API
provide better performance
limitations
flexibility
cannot jointly optimize retrieval of simple and complex data
do not typically support transaction
Object Database Middleware
Clients no directly access media servers
clients send SQL statements to middleware
relieves the user of knowing a separate API
provides location independence
limitations
can suffer performance problems
same performance problems as with specialized media servers
transaction performance can be slow
can provide transaction
object-relational DBMS
support user-defined types
subtable families
arrays
reference
row data types
limitations
reliability
Implementation errors can affect the integrity of data
third-party data types can be subject to viruses
Object-oriented DBMS
not important
ad hoc query
query optimization
transaction
support for complex data in large software systems