Data Base Administration 1

51. What is a database instance? Explain.
A database instance (Server) is a set of memory structure and background processes that access a set of database files. The processes can be shared by all of the users.

The memory structure that is used to store the most queried data from database. This helps up to improve database performance by decreasing the amount of I/O performed against data file.

52. What is Parallel Server?
Multiple instances accessing the same database (only in multi-CPU environments)


53. What is a schema?
The set of objects owned by user account is called the schema.

54. What is an index? How it is implemented in Oracle database?
An index is a database structure used by the server to have direct access of a row in a table. An index is automatically created when a unique of primary key constraint clause is specified in create table command

55. What are clusters?
Group of tables physically stored together because they share common columns and are often used together is called cluster.