190 Part I EXAM PREPARATION A PPLY YOUR
190 Part I EXAM PREPARATION A PPLY YOUR K NO WLEDGE 11. A, E. The UNIQUE constraint on the Parts table UPC column is required first, so that the FOREIGN KEY constraint can be applied from the OrderDetails.UPC column referencing Parts.UPC. This achieves the referential integrity requirement. It also reduces I/O required during joins between Parts and OrderDetails, which make use of the FOREIGN KEY constraint defined. For more information, see Maintaining Referential Integrity. 12. A. To obtain the physical storage sequence of the data, you must use a clustered constraint or index. Although a Primary Key would also provide for the level of uniqueness, it is not the desired key for this table. For more information, see Unique Indexing in Chapter 10. 13. C. A single table could provide all the necessary information with no redundancy. The table could easily be represented using a self-join operation to provide the desired reporting. Join operations will be discussed in detail in the next chapter. 14. A. Using identities in this fashion enables records to be entered that have no overlap. One location would use entry values 1, 7, 13, 19; the next would have 2, 8, 14, 20; the third 3, 9, 15, 21, and so on. For more information, see Application of Integrity Options. 15. C. This is a many-to-many relationship scenario, which in SQL Server is implemented using three tables. The center table, often referred to as the connecting or joining table, is on the many side of both of the relationships to the other base table. For more information, see Maintaining Referential Integrity. Suggested Readings and Resources 1. Inside SQL Server 2000 Kalen Delaney (www.insidesqlserver.com) Not a beginner blog, but it fills in many of the gaps left out of the SQL Server blogs Online documentation. Explains fully how SQL Server stores and processes data internally. 2. SQL Server 2000 blogs Online Creating and Maintaining Databases (Look particularly at the sections on indexes, views, and triggers.) Transact-SQL Reference (Use this as a resource for the specific syntax requirements of each statement, as well as some code examples.) Optimizing Database Performance (Focus on Database and Application Design.) Troubleshooting: Server and Database Troubleshooting 3. MSDN Online Internet Reference (http://msdn.microsoft.com) Transact SQL Overview (/library/psdk/sql/ts_tsqlcon_6lyk.htm) Transact SQL Syntax Conventions (/library/psdk/sql/ts_syntaxc_9kvn.htm) Transact SQL Tips (/library/psdk/sql/ac_8_qd_14_2kc3.htm)
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