An index is a physical mechanism used to store and access the rows of a table. Indexes on tables in a relational database function much like indexes in books, they speed up information retrieval.
In general, Teradata Database uses indexes to:
Indexed access is usually more efficient than searching all rows of a table.
Only one row of a table can have a particular value in the column or columns defined as a unique index.
Teradata Database supports the following types of indexes:
These indexes are discussed in the following sections.