What is an Index Organized Table (IOT)?
An Index Organized Table (IOT) is a table that is sorted internally as an index. Other database systems such as MAXDB or DB2 use IOTs by default, whereas on Oracle, you must configure this function explicitly. 2. What are the advantages of IOTs? An IOT offers advantages over a normal table: • The IOT combines a table and index in one, saving you the effort of creating an index. • Queries using the fields of this index result in fewer block accesses, since all of the information is already in the index blocks and an additional access to table blocks is no longer necessary. This fact means there are significant performance gains, especially when compared to indexes with a high clustering factor. The higher the number of blocks that have to be read on average from the hard disk (see also Note 832343), the more important these gains. 3. What are the technical attributes of an IOT? The IOT is always defined on the basis of a PRIMARY KEY constraint. In just the same way as the UNIQUE KEY con
