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Unit 8: Database System
Hypermedia Log Databases Notes
The World Wide Web can be thought of as a database, albeit one spread across millions of
independent computing systems. Web browsers “process” this data one page at a time, while
Web crawlers and other software provide the equivalent of database indexes to support search
and other activities.
Operational Log Database
These databases store detailed data about the operations of an organization. They are typically
organized by subject matter, process relatively high volumes of updates using transactions.
Essentially every major organization on earth uses such databases. Examples include customer
databases that record contact, credit, and demographic information about a business’ customers,
personnel databases that hold information such as salary, benefits, skills data about employees,
Enterprise resource planning that record details about product components, parts inventory, and
financial databases that keep track of the organization’s money, accounting and financial dealings.
8.1.2 Database Models
8.1.2.1 Object Database Models
In recent years, the object-oriented paradigm has been applied in areas such as engineering and
spatial databases, telecommunications and in various scientific domains. The conglomeration of
object oriented programming and database technology led to this new kind of database. These
databases attempt to bring the database world and the application-programming world closer
together, in particular by ensuring that the database uses the same type system as the application
program. This aims to avoid the overhead (sometimes referred to as the impedance mismatch)
of converting information between its representation in the database (for example as rows in
tables) and its representation in the application program (typically as objects). At the same time,
object databases attempt to introduce key ideas of object programming, such as encapsulation
and polymorphism, into the world of databases.
A variety of these ways have been tried [by whom?] for storing objects in a database. Some products
have approached the problem from the application-programming side, by making the objects
manipulated by the program persistent. This also typically requires the addition of some kind
of query language, since conventional programming languages do not provide language-level
functionality for finding objects based on their information content. Others [which?] have attacked
the problem from the database end, by defining an object-oriented data model for the database,
and defining a database programming language that allows full programming capabilities as
well as traditional query facilities.
Figure 8.4: Object Database Model
Multimedia ODBMS
Media One Media Two Media Three
Media Two
Transport Summarize
Summarize Transport Summarize Transport
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