15.00 - Advantages and Disadvantages of Multicolumn NUPIs - Teradata Database

Teradata Database Design

prodname
Teradata Database
vrm_release
15.00
category
User Guide
featnum
B035-1094-015K

Advantages and Disadvantages of Multicolumn NUPIs

The following table lists the advantages and disadvantages of multicolumn NUPIs.

 

                               Advantages

                           Disadvantages

Singularity is enhanced.

Primary index retrievals are possible only when you specify all of the NUPI columns in the WHERE clause of your SELECT requests.

Number of rows per value is lessened.

Partial primary index values cannot be hashed.

Selectivity is enhanced.

Usability is decreased.

                                                              Summary Statement

The more columns defined for a NUPI, the closer it is to being unique.

The more columns defined for a NUPI, the less generalized its use.