About Relational Databases
Introduction to Oracle Database 1-3
In this case, the RDBMS determines how things should be done and carries out the
operation. For example, after an application queries a table, the database may use
an index to find the requested rows, read the data into memory, and perform
many other steps before returning a result to the user. The RDBMS stores and
retrieves data so that physical operations are transparent to database applications.
Oracle Database is an RDBMS. An RDBMS that implements object-oriented features
such as user-defined types, inheritance, and polymorphism is called an
object-relational database management system (ORDBMS). Oracle Database has
extended the relational model to an object-relational model, making it possible to store
complex business models in a relational database.
Brief History of Oracle Database
The current version of Oracle Database is the result of over 30 years of innovative
development. Highlights in the evolution of Oracle Database include the following:
■ Founding of Oracle
In 1977, Larry Ellison, Bob Miner, and Ed Oates started the consultancy Software
Development Laboratories, which became Relational Software, Inc. (RSI). In 1983,
RSI became Oracle Systems Corporation and then later Oracle Corporation.
■ First commercially available RDBMS
In 1979, RSI introduced Oracle V2 (Version 2) as the first commercially available
SQL-based RDBMS, a landmark event in the history of relational databases.
■ Portable version of Oracle Database
Oracle Version 3, released in 1983, was the first relational database to run on
mainframes, minicomputers, and PCs. The database was written in C, enabling the
database to be ported to multiple platforms.
■ Enhancements to concurrency control, data distribution, and scalability
Version 4 introduced multiversion read consistency. Version 5, released in 1985,
supported client/server computing and distributed database systems. Version 6
brought enhancements to disk I/O, row locking, scalability, and backup and
recovery. Also, Version 6 introduced the first version of the
PL/SQL language, a
proprietary procedural extension to SQL.
■ PL/SQL stored program units
Oracle7, released in 1992, introduced PL/SQL stored procedures and triggers.
■ Objects and partitioning
Oracle8 was released in 1997 as the object-relational database, supporting many
new data types. Additionally, Oracle8 supported partitioning of large tables.
■ Internet computing
Oracle8i Database, released in 1999, provided native support for internet protocols
and server-side support for Java. Oracle8i was designed for internet computing,
enabling the database to be deployed in a multitier environment.
■ Oracle Real Application Clusters (Oracle RAC)
Oracle9i Database introduced Oracle RAC in 2001, enabling multiple instances to
access a single database simultaneously. Additionally, Oracle XML Database
(Oracle XML DB) introduced the ability to store and query XML.
■ Grid computing