Advantages and disadvantages of non cluster index

Thanks Allen for your reply my Table doesn't have clustered index only one non clustered index is there i am using varchar and timestamp data types below is the index i have created

 CREATE NONCLUSTERED INDEX [Inx_SiteTank] ON [dbo].[SiteTankInventory] 
 (
  [InventoryDate] ASC
 )
 INCLUDE ( [SiteID], 
         [TankID], 
         [InventoryTime], 
         [InventoryGross], 
         [InventoryNet], 
         [ProductHeight], 
         [Ullage], 
         [WaterHeight], 
         [WaterVolume], 
         [Temperature])     
 WITH (PAD_INDEX  = OFF, 
 STATISTICS_NORECOMPUTE  = OFF, 
 SORT_IN_TEMPDB = OFF,     
 IGNORE_DUP_KEY = OFF, 
 DROP_EXISTING = OFF, 
 ONLINE = OFF, 
 ALLOW_ROW_LOCKS  = ON, 
 ALLOW_PAGE_LOCKS  = ON) 
 ON [PRIMARY]

 GO

My advice then would be to look for a clustered index that would be appropriate for the table and then (re)consider NCIs after that.

Thanks Fatherjack, for your reply but we have duplicates in that table i mean repeated columns

@sravan you can have a non-unique clustered index on say (SiteID,TankID)...looking at your other question, you will want a non-clustered index on InventoryDate.

@sravan regardless of if you have duplicate values, you can still place a clustered index on the table. They do work better if they're unique, but they don't have to be. You're storing this table as a heap and then adding non-clustered indexes. That is a very inefficient way to do it. Listen to @Fatherjack, he knows what he's talking about.