Q6: Write down a SQL query to create the given relations with the following specifications. CUSTOMER CUSCODE CUS_LNAME CUS FNAME CUS INITIAL CUS AREACODE CUS PHONE INVOICE IN NUMBER CUS.CODE INV_DATE Apply the Primary key constraint on CUS_CODE in Customer table. Apply the Primary Key constraint on INV_NUMBER in INVOICE table. Apply the NOT NULL constraint on CUS_FNAME. Apply the Foreign key constraint on CUS_CODE in INVOICE table. Apply the CHECK constraint on CUS_AREACODE that CUS_AREACODE could not be equal to 0