One of the challenges design teams face when implementing Teradata design solutions is choosing indexes which help improve performance. What happens if the primary index is not the same as the primary key, and how does one validate that the design decision is correct?

The primary key of a relational table uniquely identifies each record in that table. A logical data model should specify the primary key (PK). If this specification is absent or not clear, the data modeler must provide this information. Indexes are physical design concepts and are related to data base performance. PKs are used for referential integrity, for logical correctness within the data model, and may be NULL. Primary indexes (PI), on the other hand, a physical mechanism for storage, are defined by the SQL create table, may be unique or non-unique, and can allow for changes in the data.