a2zinterviews

11.	what is null value?
	Null Value is neither zero nor it is a blank space. It is some unknown value which occupies 4 bytes of space of memory in SQL.

12.	Define transaction?
	A transaction is a sequence of SQL statements that Oracle Database treats as a single unit.

13.	what is the difference between sql&oracle?
	SQL is Stuctured Query Language.Oracle is a Database.SQL is used to write queries against Oracle DB.

14.	What are different Oracle database objects?
	TABLES VIEWS INDEXES SYNONYMS SEQUENCES TABLESPACES

15.	What is hash cluster?
	A row is stored in a hash cluster based on the result of applying a hash function to the row's cluster key value. All rows with the same hash key value are stores together on disk.