$_ =~ /^ALTER\s+TABLE\s+(\w+)\s+ADD\s+CONSTRAINT\s+(\w+)\s+PRIMARY\s+KEY\s+\(\s*(.)\s*)/;

 $table=$1;
 $name=$2;
 $col=$3;


---DATA---
ALTER TABLE ORDERS ADD CONSTRAINT PK_ORDER_ORDER_NUM PRIMARY KEY ( ORDER_NUM) ;
ALTER TABLE ORDER_ITEMS ADD CONSTRAINT PK_ORDER_NUM_ITEMS PRIMARY KEY ( ORDER_NUM, ITEM_NUM, SUB_TYPE ) ;