--FIND COLUMNS THAT ARE PRIMARY KEY AS WELL AS FOREIGN KEY - SQL SERVER 2008
SELECT
    CU.TABLE_NAME, CU.COLUMN_NAME
FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE CU
WHERE CU.CONSTRAINT_NAME IN (SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
WHERE CONSTRAINT_TYPE = 'PRIMARY KEY') AND 
COLUMN_NAME IN (SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE TABLE_NAME = CU.TABLE_NAME AND
COLUMN_NAME = CU.COLUMN_NAME AND 
CONSTRAINT_NAME IN (SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
WHERE CONSTRAINT_TYPE = 'FOREIGN KEY'))