After completing this lesson, you should be able todo the following:
Compare and evaluate the different storage structures
Examine different data access methods
Implement different partitioning methods
Tablespaces and Data Files
Databases, tablespaces, and data files are closely related, but they have important differences:
An Oracle database consists of one or more logical storage units called tablespaces, which collectively store all of the database’s data.
Each tablespace in an Oracle database consists of one or more files called data files, which are physical structures that conform with the operating system in which Oracle is running.
A database’s data is collectively stored in the data files that constitute each tablespace of the database.
As a database management system, the management of Oracle file structures is critically important to the successful operation of any system. The Oracle administrator must understand all levels of Oracle file management, including data file management principles, tablespace management principles, and the storage of individual objects within the tablespaces. As Oracle has evolved into one of the world's most complex database management systems, it is imperative that all Oracle professionals understand how their information is stored both at the logical and physical level.
With Oracle Real Application Clusters (as with any other Oracle database) the
Oracle Instance (the processes and memory structures allocated on a server to
allow access to the data) is de-coupled from the Oracle Database (the physical
structures residing on the storage, which actually hold the data. These structures are
commonly known as ‘datafiles’).
However, a clustered database (using more than one instance) differs from a single
instance database in a way that the database can be accessed by multiple instances