Tables with a large number of rows can have lengthy load times. The UNION ALL view is one way to address this issue.
SAP Sybase IQ lets you partition tables by splitting the data into several separate base tables (for example, by date). You then join them back together into a logical whole by means of a UNION ALL view.
UNION ALL views are simple to administer. If the data is partitioned by, for example, month, you can drop an entire month’s worth of data by deleting a table and updating the UNION ALL view definition appropriately. You can have many view definitions for a year, a quarter, and so on, without adding extra date range predicates.