title: Add primary key column in SQL table
body: <p>I am student of RDBMS.</p>
  
  <p>I have very basic question let say I have one existing Table in SQL server. What will be script to alter table.</p>
  
  <ul>
  <li>Drop Column 'RowId' if exist.</li>
  <li>Drop contraint if exist.</li>
  <li>Add one new column 'RowId' into table.</li>
  <li>Make this column as primary key.</li>
  <li>Autoincrement type int.</li>
  </ul>