a2zinterviews

46.	What is SYSTEM tablespace and when is it created?
	Every Oracle database contains a tablespace named SYSTEM, which is automatically created when the database is created. The SYSTEM tablespace always contains the data dictionary tables for the entire database.

47.	Which date function returns number value?
	months_between

48.	what is integrity constrains?
	Integrity constraints are used to ensure accuracy and consistency of data in a relational database.

49.	What is the difference between Explicit and Implicit Cursors?
	An Implicit cursor is one created "automatically" for you by Oracle when you execute a query. It is simpler to code An Explicit cursor is one you create yourself. It takes more code, but gives more control - for example, you can just open-fetch-close if you only want the first record and don't care if there are others DBA_DATA_FILES.

50.	what are primary keys?
	Primary key are used to uniquely identify each row of the table. A table can have only one primary key.