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Unformatted text preview: Conversion to BCNF To convert this table to BCNF, first change the primary key to (A,C). So the new table is TABLE (A,C ,B,D) At this point the table is in 1NF but not in 2NF (partial dependency exists C B). We will now follow the algorithm to decompose the offending dependency. TABLE 1(A, C , D) TABLE2 (C, B) These two tables are now in BCNF! Now consider the example in Lecture 3, Slide 3-13. The table ITEM (ItemNumber , Type, AcquisitionCost) has the functional dependency – Type (ItemNumber, AcquisitionCost) In other words, we have two candidate keys in that table ItemNumber and Type. Therefore, all determinants are candidate keys. Hence, this table is in BCNF and needs no further decomposition. Had we not made the assumption that Type (ItemNumber, AcquisitionCost), then the table would be in 3NF....
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- Spring '06
- Accounting, Database normalization, BCNF