Databases Reference
In-Depth Information
In the later steps, we execute the same queries as in step 2, step 3, and step 4 with the
index in place. The corresponding execution plan is as follows:
In the first query, the presence of the index is very important, because the sort operation is
avoided. To obtain the results (in the same order of the index) a simple
INDEX
FULL
SCAN
is required, because all the columns we select in the query are part of the index, so the
optimizer goes for index full scan.
