Repeats a statement for each primary key column in a table.
In a trigger for the table TITLEAUTHOR, the following macro:
message .PKCOLN("'%COLUMN% is a primary key column'","",",",";")
            generates the following trigger script:
message 'AU_ID is a primary key column',
    'TITLE_ISBN is a primary key column';
            For columns, the macro PKCOLN only accepts the variable %COLUMN%.