Types of Oracle Tables:
=======================
=> There are two types of tables in oracle:
	1) Database tables
	2) Non-Database tables
=> When the data can be store in the tables those tables are called "database tables".
Ex: Employee table, Student table, Product table, Orders tables etc.

=> When the tables does not contains any information are called as "non-database tables".
=> The non-database tables are also called as "temporary tables".
Ex: dual
=> To deal with:
	arithmetic expressions
	pseudo codes 
non-database tables.

Ex: select sysdate from dual;
select (2*3/5+97-28) from dual;

Functions:
==========
=> function is a named block
which contains set of instructions
to perform the specific task.
=> the functions in SQL are classified into 2-types:
	1) Pre-defined functions/Built-in functions
	2) User-defined functions
=> The pre-defined functions can be given by the system.
the pre-defined functions are classified into three types:
	1) Single line functions
	------------------------
	=> can define all columns of the table
	=> can return more than one value.

	2) Multi-line functions
	------------------------
	=> can define on the table for only one time
	=> it can return only one value.

	3) Miscellaneous functions

1) Single line functions:
==========================
1) length():
------------
=> can return number of characters of the data which includes white space characters also.

Ex:
1) select length('Welcome To Ashok IT!') from dual;
2) select orderName, length(orderName) from orders;

2) initcap():
-------------
=> can convert the text/string-data into title case.
Here:
	title case: the first letter of each word in the string-data convert into "upper-case".
	and remaining are into "lower case".

Ex:
1) select initcap('welcome to ashok it!') from dual; ==> without the alias name
2) select initcap('ravi kumar') as title from dual; ==> with alias name

3) chr():
---------
=> chr() can accept an ASCII (0 to 255)
and return the corresponding character.

Ex:
select chr(99) from dual;

4) ascii():
-----------
=> ascii() can accept a character
and returns its corresponding ASCII value.

Ex:
select ascii('R') from dual;
select ascii('B') as character from dual;

5) upper():
-----------
=> upper() can change the case of the string-data into upper case.

Ex: select upper('ashok it') from dual;

6) lower():
------------
=> lower() can change the case of the string-data into lower case.

Ex: select lower('ashok it') as LowerCase from dual;

7) reverse():
-------------
=> reverse() can reverse the string-data.

Ex:
select reverse('ashok it') as reversed from dual;