Types of indexes

Adaptive Server provides two types of indexes:

You can create only one clustered index on a table because there is only one possible physical ordering of the data rows. You can create up to 249 nonclustered indexes per table.

A table that has no clustered index is called a heap. The rows in the table are in no particular order, and all new rows are added to the end of the table. Chapter 7, “Data Storage,” discusses heaps and SQL operations on heaps.