Two complete pages of Chapter 3 were spent covering this common relationship between the INVOICE table and the LINE (or INVOICE LINE as it is more commonly referred in industry) 8 Table name: INVOICE Primary key: INV NUMBER Foreign key: CUS CODE Table name: LINE Primary key: INV NUMBERLINE NUMBER Foreign key: INV_NUMBER, PROD CODE CUS CODE INV ATE 10014 08-Mar-14 10011 08-Mar-14 10012 08-Mar-14 10011 09-Mar-14 LINE 1001 1001 1002 1003 1003 1003 1004 1004 PROD CODE LINE UNITS LINE 1123-21UUY 2 SRE-657UG 1QER-34256 1 ZZX132450 2 SRE-657UG 3001278-AB 1 001 278-AB 2 SRE-657UG 189.99 2.99 18.63 6.79 2.99 12.95 12.95 2.99 The primary key of the LINE table is known as what? A redundant key A composite key A duplicate key A bridge key