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Lesson 1

Introduction to Understanding Oracle Database Architecture and Creation

An Oracle database is composed of files. There are several types of files, and it is important that you as the DBA understand the purpose of each file, as well as what it contains. This module will help you do that.
Oracle DB Architecture
When you have completed this module, you will be able to:
  1. Identify the different files used by a database
  2. Edit and understand a database initialization file
  3. Explain the use and importance of redo logs for instance recovery
  4. Understand the relationship between tablespaces and datafiles

Tablespaces, Datafiles, and Control Files

Oracle stores data logically in tablespaces and physically in datafiles associated with the corresponding tablespace. Figure 3-1 illustrates this relationship. Databases, tablespaces, and datafiles are closely related, but they have important differences:
  1. An Oracle database consists of one or more logical storage units called tablespaces, which collectively store all of the database's data.
  2. Each tablespace in an Oracle database consists of one or more files called datafiles, which are physical structures that conform to the operating system in which Oracle is running.
  3. The data of a database is collectively stored in the datafiles that constitute each tablespace of the database. For example, the simplest Oracle database would have one tablespace and one datafile. Another database can have three tablespaces, each consisting of two datafiles (for a total of six datafiles).

Figure 3-1 Datafiles and Table Objects within a Tablespace
Figure 3-1: Datafiles and Table Objects within a Tablespace

When ready, go to the next lesson, and begin.