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