Database Reference
In-Depth Information
4.1
Summarize the premise of this chapter.
4.2
When you receive a set of tables, what steps should you take to assess their structure
and content?
4.3
Show SQL statements to count the number of rows and to list the top 15 rows of the
RETAIL_ORDER table.
4.4
Suppose you receive the following two tables:
DEPARTMENT (
DepartmentName
, BudgetCode)
EMPLOYEE (
EmployeeNumber
, EmployeeLastName, EmployeeFirstName,
Email, DepartmentName)
and you conclude that EMPLOYEE.DepartmentName is a foreign key to DEPARTMENT
.DepartmentName. Show SQL for determining whether the following referential integ-
rity constraint has been enforced:
DepartmentName in EMPLOYEE must exist in DepartmentName in
DEPARTMENT
4.5
Summarize how database design principles differ with regards to the design of updat-
able databases and the design of read-only databases.
4.6
Describe two advantages of normalized tables.
4.7
Why do we say that data duplication is only reduced? Why is it not eliminated?
4.8
If data duplication is only reduced, how can we say that the possibility of data inconsis-
tencies has been eliminated?
4.9
Describe two disadvantages of normalized tables.
4.10
Suppose you are given the table:
EMPLOYEE_DEPARTMENT (
EmployeeNumber
, EmployeeLastName,
EmployeeFirstName, Email, DepartmentName, BudgetCode)
and you wish to transform this table into the two tables:
DEPARTMENT (
DepartmentName
, BudgetCode)
EMPLOYEE (
EmployeeNumber
, EmployeeLastName, EmployeeFirstName,
Email,
DepartmentName
)
Write the SQL statements needed for filling the EMPLOYEE and DEPARTMENT tables
with data from EMPLOYEE_DEPARTMENT.
4.11
Summarize the reasons explained in this chapter for not placing ZIP code values into
B C N F.
4.12
Describe a situation, other than the one for ZIP codes, in which one would choose not
to place tables into BCNF. Justify your decision not to use BCNF.
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