DBIx::Class primary key if underlying RDBMS table lack one

The Significance and Importance of Primary Keys

The concept of a primary key in DBIx::Class warrants special discussion. The formal definition (which somewhat resembles that of a classic RDBMS) is a unique constraint that is least likely to change after initial row creation. However this is where the similarity ends. Any time you call a CRUD operation on a row (e.g. delete, update, discard_changes, etc.) DBIx::Class will use the values of of the primary key columns to populate the WHERE clause necessary to accomplish the operation. This is why it is important to declare a primary key on all your result sources even if the underlying RDBMS does not have one. In a pinch one can always declare each row identifiable by all its columns:

__PACKAGE__->set_primary_keys (__PACKAGE__->columns);