CREATE TABLE [dbo].[Voters](
	[RollNum] [int]				UNIQUE,
	[Name] [char](20)			NOT NULL,
	[Email] [varchar](20)		NULL,
	[Age] [int]					CHECK(AGE>18) NOT NULL,
	[Gender] [char](10)			CHECK(GENDER IN ('M','F','O')),
	[RegisteredDate] [datetime] DEFAULT (getdate()),
);

--Adding a new column
ALTER TABLE Voters ADD AADHAR INT CHECK(LEN(AADHAR) = 12)

--Modifying an existing column
ALTER TABLE Voters ALTER column GENDER Char(1)

--Dropping an existing column
alter table voters drop constraint UQ__Voters__1D2F169CBC62AA70
ALTER TABLE Voters Drop column RollNum

--Drop a table - Deletes table structure along with data
drop table Voters

SELECT * FROM VOTERS;