106 Part I EXAM PREPARATION A PPLY YOUR
106 Part I EXAM PREPARATION A PPLY YOUR K NO WLEDGE tion because you already have an IIS server available. Whether you have Internet access or not is irrelevant because everything can be performed in-house using an HTML or XML solution across the network. For more information, see the Internet Applications section. 4. A, C. By definition timestamp and unique identifier data types are guaranteed to be globally unique. The timestamp is an automatically entered value. The uniqueidentifier is usually entered using a NEWID() function to generate the uniqueidentifier. For more details, see the Using Appropriate Data Types section. 5. A, C, D. An Identity provides for uniqueness by incrementing a value continually, and therefore it is a standard choice for a column that requires a unique value. Unique indexes and unique constraints enforce the uniqueness of entered values and do not let any entry come into the system that already exists. For more information, see the section titled Entity Integrity. 6. A, C. Fullname can be broken down into first- name and lastname and is therefore not in its most decomposed form. This breaks the first normal form rule of normalization. The salesman name should not be stored in this entity because it depends on the salesmanID and not the customerID. This breaks the third normal form rule of normalization. For more information, see Understanding Database Normalization. 7. B. An automobile s VIN number, though unique, is character data and is much too large to use as a Primary Key. This is a perfect situation for an automatically incremented numeric surrogate key that will take up a lot less storage space. For more information, consult the section on Primary Keys. 8. D. According to byte sizes, int would take a quarter of the space of the current nchar(5) setting. Smallint would even be better, but has an upper limit of 32,767. Char(5) would cut the space used in half but is not as good as using actual numeric storage. Whenever a variable is going to contain only numbers, numeric storage is always more efficient. For more details, see the Using Appropriate Data Types section. 9. D. This is a tricky question to resolve, and if it were not for the space restriction there would be a temptation to use characters for the storage. At 8 bytes a piece (double that of int) the easier technique would be to track days from the beginning of recorded time in an integer. (2001 1300) 365 1/4 requires 6 digits, and therefore int is the closest to the size required. Datetime allows dates in only the 1700s and smalldatetime in the 1900s. For more information, see the Using Appropriate Data Types section. 10. B. The many-to-many relationship in this scenario occurs because many contractors can work on a Suggested Readings and Resources single site, and a single contractor can work at many sites. The connection needs to involve both sites and contractors for an appropriate relationship to be drawn. For further information, refer to the Understanding Entity Relationships section. 11. C. SQL Server is ideal for this situation.
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