... Design for Relational Databases - 105 the unordered scan.3 Similar considerations can be applied for DELETE and INSERT statements. The reader is referred to [33] for details on the cost formulas. ... Design for Relational Databases l 107 Of the 20 columns in PARTS AND ORDERS, only 5 are plausible for statement (S3): PARTNO, WEIGHT, and QONHAND for PARTS, and PARTNO and SUPPNO for ORDERS. ... columns (6 for the costs of clustered indices, 6 for the nonclustered indices, and 1 for sequential scan). Ignoring memory costs for simplicity, the results of index elimination for that cost...