Chapter 3 PHYSICAL DATABASE DESIGN AND IMPLEMENTATION 189
Chapter 3 PHYSICAL DATABASE DESIGN AND IMPLEMENTATION 189 APPLY YOUR KNOWLEDGE desired and would have to be complemented with the actions of a trigger. Disabling referential integrity is a poor solution to any problem, especially considering the medical nature of this application and the possible ramifications. For more information, see Trigger Utilization. 3. D. Because the IMAGE data will seldom be accessed, it makes sense to get the remainder of the data away from the images while moving the log away from the data. This will help to improve performance while providing optimum recover- ability in the event of a failure. For more information, see Using Filegroups. 4. D. Good controllers suitable for database use will have a battery backup. The battery should be regularly tested under controlled circumstances. Disabling caching if currently in place is likely to affect performance, as will enabling torn page detection. Torn page detection might help point out whether data is being corrupted because of failures. A maintenance plan is recommended, although it is not an entire solution in its own right. 5. A. Because a trigger is already in place, it can easily be altered to perform the additional data check. A rule cannot provide the required functionality because you cannot compare the data. The CHECK constraint may be a viable solution but you would have to alter the trigger to check for an error and provide for nested operations. The number of triggers firing should be kept to a minimum. To accommodate additional triggers, you would have to check the order in which they are being fired and again set properties of the server and database accordingly. For more information, see Trigger Utilization. 6. C. Because the majority of the reporting is going to be performed using the storage location, it would be the likely candidate. The clustered index represents the physical order of the data and would minimize sorting operations when deriving the output. For more information, see Index Organization. 7. C. Simple Recovery uses the least amount of log space for recording changes to the database. Full recovery uses the most space because it fully logs any bulk operations. Bulk recovery represents a mid-point between the two. Auto Close frees up resources at the earliest possible point during process execution, and Auto Shrink minimizes the space used in the file system by periodically reducing the files when there is too much unused space. For more information, see Use of Recovery Models. 8. B, C, D, E. All these options have activities that provide or alter data so that it does not have to be performed as an entry operation. In the case of NULL, data need not be provided, possibly because the column contains non-critical information. For more information, see Table Characteristics. 9. D. Use AUTOGROW to set the system so that the files will grow as needed for the addition of new data. You may want to perform a planned shrinkage of the database as part of the quarter-ending process and save on overhead by leaving the AUTOSHRINK option turned off. For more information, see Creating Database Files and Filegroups. 10. A. You need to add a constraint to prevent negative data entry. The best method of implementing this functionality is a constraint. A trigger has too much overhead and the RULE is not accurately implemented. A procedure could handle the process but is normally only used for processes requiring more complex logic. For more information, see Table Characteristics.
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