Database Reference
In-Depth Information
3.1
Name three sources for databases.
3.2
What is the basic premise of this and the next chapter?
3.3
Explain what is wrong with the table in Figure 3-2.
3.4
Define each of the terms listed in Figure 3-3.
3.5
Describe the characteristics of a table that make it a relation. Define the term
domain
and explain the significance of the
domain integrity constraint
to a relation.
3.6
Give an example of two tables that are not relations.
3.7
Suppose that two columns in two different tables have the same column name. What
convention is used to give each a unique name?
3.8
Must all the values in the same column of a relation have the same length?
3.9
Explain the three different sets of terms used to describe tables, columns, and rows.
3.10
Explain the difference between functional dependencies that arise from equations and
those that do not.
3.11
Explain the intuitive meaning of the functional dependency.
PartNumber
S
PartWeight
3.12
Explain the following statement: “The only reason for having relations is to store in-
stances of functional dependencies.”
3.13
Explain the meaning of the expression:
(FirstName, LastName)
S
Phone
3.14
What is a composite determinant?
3.15
If (A, B)
S
C , then can we also say that A
S
C?
3.16
If A
S
(B, C), then can we also say that A
S
B?
3.17
For the SKU_DATA table in Figure 3-1, explain why Buyer determines Department, but
Department does not determine Buyer.
3.18
For the SKU_DATA table in Figure 3-1, explain why:
SKU_Description
S
(SKU, Department, Buyer).
3.19
If it is true that
PartNumber
S
PartWeight
does that mean that PartNumber will be unique in a relation?
3.20
Under what conditions will a determinant be unique in a relation?
3.21
What is the best test for determining whether a determinant is unique?
3.22
What is a composite key?
3.23
What is a candidate key?
3.24
What is a primary key? Explain the significance of the
entity integrity constraint
to a
primary key.
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