Include PRIMARY KEY in the
ADD clause to add a primary key to a table definition. The primary key is a unique index that does not include null values. When you specify a primary key, Pervasive PSQL creates a unique index with the specified attributes on the defined group of columns.
Include PRIMARY KEY in the ADD clause with the ALTER
TABLE statement to add a primary key to a table definition.
Include a PRIMARY KEY clause with the CREATE
TABLE statement to add a primary key to a table definition.
To define referential constraints on your database, you must include a PRIMARY KEY clause to specify the primary key on the parent table. The primary key can consist of one column or multiple columns but can only be defined on columns that are not null. The columns you specify must also appear in the column Definitions list of the
CREATE TABLE statement.