## Deletes/Updates

Delete selectivity <percentage>%: <number_of> deletes, <number_of> rows read, <number_of> rows qualified

Update selectivity <percentage>%: <number_of> updates, <number_of> rows read, <number_of> rows qualified

### Explanation

The ratio of read rows to modified rows is poor for UPDATE or DELETE statements.

Before UPDATE and DELETE statements can modify or delete rows, the row must be located in the table. The same access strategies are used as in a SELECT statement.

### User Response

Find the statement that causes this poor ratio of read rows to found rows, and check the access strategies for this statement.

For information on creating optimized SQL statements, see the SQL Optimizer documentation.