What is a characteristic of a Nonunique Primary Index (NUPI)?

A Nonunique Primary Index (NUPI) allows multiple rows with the same index value, which is the defining feature of this type of index in Teradata. When a table is defined with a NUPI, the database can store duplicate values in the indexed column, enabling the retrieval of multiple rows that share the same index value during query operations. This characteristic allows for a greater variety of data structures where the uniqueness of index values is not necessary.

This differs from a Unique Primary Index (UPI), which would ensure that each index value is distinct across the rows of the table, thereby maintaining uniqueness and typically leading to a different way of querying and organizing data. The other options convey different attributes that are not applicable to NUPIs—it does not ensure distinct values, does not inherently guarantee faster query performance, nor does it directly aim to simplify table joins in the same manner as other index types might.