One of the T-SQL enhancemtns in SQL Server 2012 addition of Sequence.  You can use sequence to generate a sequential number that can use utilized for various purpose. Here is simple example of using Sequence to populate sequential number to a table.

  

Create Table dbo.Employee
(
EmployeeID Int,
FirstName Varchar(30)
);

Create Sequence dbo.EmpIDSeq
As Int Start with 1 increment by 1;

Insert Into Employee(EmployeeID,FirstName)
values
(next value for dbo.EmpIDSeq,'John'),
(next value for dbo.EmpIDSeq,'Mike');

Select * from Employee;
You can create the same using Managemet Studio UI - Database/Programmability/Sequences.