text: --Upgrade from version 2 to version 3 creates a new table
  CREATE TABLE Account_Details (
      Account_ID INT,
      EMail VARCHAR(20),
      FOREIGN KEY (Account_ID) REFERENCES Account (Account_ID)
  );
  --and copy emails from existing accounts into it.
  INSERT INTO Account_Details SELECT Account_ID,EMail FROM Account;
  --finally the email column is removed from Account table.
  ALTER TABLE Account DROP COLUMN EMail;
  