Use positional updates and deletes or SQLSetPos to update data. Although positional updates do not apply to all types of applications, developers should use positional updates and deletes when it makes sense. Positional updates (using “update where current of cursor” or using SQLSetPos) allow the developer to signal the ODBC driver to “change the data here” by positioning the database cursor to the appropriate row to be changed. The designer is not forced to build a complex SQL statement and simply supplies the data that will be changed.
In addition to making the application more easily maintainable, positional updates usually result in improved performance. Because the database server is already positioned on the row for the Select statement in process, performance-expensive operations to locate the row to be changed are not needed. If the row must be located, the server usually has an internal pointer to the row available (for example, ROWID).
