Basic rules that define PI in Teradata

What are the basic rules that define how PI is defined in Teradata?

Answer:

The following rules govern how Primary Indexes in a Teradata Database must be defined as well as how they function:

•         One Primary Index per table.

•         A Primary Index value can be unique or non-unique.

•         The Primary Index value can be NULL.

•         The Primary Index value can be modified.

•         The Primary Index of a populated table cannot be modified.

•         A Primary Index has a limit of 64 columns.