Adding an index to a What-If scenario

To add a new index

1. Select the table as described in Creating and editing a What-If index scenario.
2. Click Add.
3. In the Index Attributes tab, define the new index:
   1. At Index name, enter the name that you want to use.
   2. At Unique rule, accept the default (Duplicate) or select Unique or Unique unless Null.
   3. Select the corresponding check boxes if you want the index to be clustering, partitioned, or padded.
   4. Click Next.
4. In the Key Columns tab, define the key columns for the index:
   1. Add columns or remove available columns from the Selected Columns pane.
   2. If you want to reorder a column, select it and use the Up  or Down  button to change the column's position.

   3. If you want to add an index on expression, click  and enter an expression. Then, click OK. You can enter any valid standard expression that SQL supports.

      Tip

      To remove an index on expression, click .

   4. Click  to sort the columns in ascending, descending, or random order.
   5. Click Next.
5. In the Index Statistics tab, define the statistics for this index:
   1. At First key cardinality, enter a positive integer (default 0) or -1 (indicating that no statistics have been gathered).
   2. At Full key cardinality , enter a positive integer (default 0) or -1 (indicating that no statistics have been gathered).
   3. At Cluster ratio , enter a number between 0 and 1 (default 0.8) or -2 (indicating that no statistics have been gathered).
   4. At Leaf pages, enter a positive integer or -1 (the default, indicating that no statistics have been gathered).
   5. At Number of Levels, enter the number of required levels (default -1).
   6. Click Finish.The wizard closes, and the results pane shows the new index with  beside it.

Where to go from here

You can now Explain and compare the new scenario.