ORACLE DATBASE ARCHITECTURE

Many materials and websites offer a different to the same Oracle Architecture. Therefore one is left confused after reading several sources. Therefore I have made an effort to pool in all the info into an understandable form. Lets see what lies beneath the giant Oracle.



Oracle database consists of 2 types:

1) Database

2) Instance



1) Database:

The database is the physical files on disk. This consists of 2 parts:

I) Physical Database Structure

II) Logical Database Structure





I) Physical Database Structure:



The Physical Database structure conists of:

i) Datafiles

ii) Control Files

iii) Redo Log Files

iv) Other files like Server Parameter files, Alert Log Files, Trace Files



II) Logical Database Structure:



The Logical Database Structure consists of:

i) Data Blocks

ii) Extents

iii) Segments

iv) Tablespaces



2) Instance:

Instance consists of:



I) Memory Structures

II) Background Processes (or just 'Processes')