Database Reference
In-Depth Information
Key Terms
aggregate function
AND criterion
attribute
calculated field
Cartesian product
comparison operator
compound condition
compound criteria
computed field
concatenation
criteria
criterion
delete query
design grid
difference
division
field
function
grouping
INTERSECT
intersection
join
join column
join line
major sort key
make-table query
minor sort key
natural join
null
OR criterion
outer join
primary key
primary sort key
product
PROJECT
qualify
query
Query-By-Example (QBE)
record
relation
relational algebra
relational database
relational operator
repeating group
secondary sort key
SELECT
sort
sort key
SUBTRACT
tuple
union
union compatible
unnormalized relation
update query
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Review Questions
1. What is a relation?
2. What is a relational database?
3. What is an unnormalized relation? Is it a relation according to the definition of the word relation?
4. How is the term attribute used in the relational model? What is a more common name for atttribute?
5. Describe the shorthand representation of the structure of a relational database. Illustrate this technique by
representing the database for Henry Books as shown in Chapter 1.
6. What does it mean to qualify a field name? How would you qualify the Street field in the Customer table?
7. What is a primary key? What is the primary key for each table in the Henry Books database shown in
Chapter 1?
8. How do you include a field in an Access query?
9. How do you indicate criteria in an Access query?
10. How do you use an AND criterion to combine criteria in an Access query? How do you use an OR criterion to
combine criteria?
11. How do you create a computed field in an Access query?
12.
In which row of the Access design grid do you include functions? What functions can you use in Access
queries?
