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. |