The Oracle database is a relational database system from Oracle corporation extensively used in product and internet-based applications in different platforms. Oracle database was developed by Larry Ellison, along with friends and former coworkers Bob Miner and Ed Oates, who had started a consultancy called Software Development Laboratories (SDL). They called their finished product Oracle, after the code name of a CIA-funded project they had worked on at a previous employer, Ampex.
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2 History 3 Version numbering conventions 4 Database-related applications 5 List of Firsts 6 External links |
Oracle stores data logically in the form of tablespaces and physically in the form of data files. Tablespaces are conceived based on the type of the data segments they contain, for e.g., Data Segments, Index Segments, Bootstrap Segments, etc. Segments in turn are made up of one or more extents. Extents are grouped based on contiguous data blocks. Data blocks are the basic unit of data storage. At the physical level, data files are made up of one or more data blocks, where the blocksize can be variable.
Oracle keeps track of data storage with the help of information stored in the System tablespace. The System tablespace contains the Data Dictionary, indexes and clusters. Data dictionary is a special collection of tables that contains information about all user objects in the database.
An Oracle database installation traditionally comes with a default schema called scott. After the sample tables have been created, the user can log into the database with the user scott and password tiger. These names come from Bruce Scott who was one of the first employees at Oracle (then Software Development Laboratories). Tiger was the name of his cat.
Software Development Laboratories was founded in 1977. In 1979 SDL changed its company name to Relational Software, Inc (RSI) and introduced their product Oracle V2 as an early commercial relational database system. The version did not support transactions but implemented the basic SQL functionality of queries and joins. There was no version 1, instead the first version was called version 2 as a marketing strategy.
In 1983, RSI was renamed Oracle Corporation to more closely align itself with its flagship product. Oracle version 3 was released which had been re-written in the C Programming Language and supported commit and rollback transaction functionalities. Platform support was extended to UNIX with this version, which until then had run on Digital VAX/VMS systems.
In 1984, Oracle version 4 was released which supported read consistency.
Starting 1985, Oracle began supporting the Client-Server model, with networks becoming available in the mid 80s. Oracle version 5.0 supported distributed querying.
In 1988, Oracle entered the products market and developed its ERP product - Oracle Financials based on the Oracle Relational Database. Oracle version 6 was released with support for PL/SQL, row-level locking and hot backups.
In 1992, Oracle version 7 was released with support for integrity constraints, stored procedures and triggers.
In 1997, Oracle version 8 was released with support for object-oriented development and multimedia applications.
In 1999, Oracle 8i was released which is more in tune with the needs of the Internet (The i in the name stands for "Internet"). The database has a native Java Virtual Machine.
In 2001, Oracle 9i was released with 400 new features including the facilty to read and write XML documents.
In 2003, Oracle 10g was released. The g stands for "Grid"; one of the sales points of 10g is that it's "grid computing ready".
Oracle's numbering conventions have confused many people; they warrant a brief explanation. Since version 8, Oracle's RDBMS release numbering has been as follows:
Some of the major database-related suites of Oracle applications are:
Data storage structure
History
Version numbering conventions
In addition to its powerful RDBMS, Oracle has released several related suites of applications. These have historically followed their own release numbering conventions. For example, Oracle Designer's upgrade path led from 6i to 2000 to 9i, when it was subsumed into Oracle Developer 9i. As of the RDBMS 10g release, Oracle seems to be making an effort to standardise all current versions of its major products on the "10g" label. This will be most confusing to Oracle Applications users, who will have to upgrade from version 11i to version 10g.Database-related applications
Newbies to Oracle who need to get it up and running should check out the comp.databases.oracle Usenet discussion groups. Users who have Oracle support contracts should turn to Oracle's Metalink website, see below (requires password).List of Firsts
External links
