C170 WGU EXAM QUIZ WITH ANSWERS PROVIDED

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C170 WGU EXAM QUIZ WITH ANSWERS PROVIDED

C1




C 170




1. CHAR: a fixed string of characters
b b b b b

2. VARCHAR: a string of variable length up to a specified maximum size.
b b b b b b b b b b b

3. Decimal data types: numbers with fractional values. FLOAT and DECIMAL
b b b b b b b b b

4. Time data types: represent date, time or both. For e.g: DATE, TIME, DATE
b b b b b b b b b b b b

TIME, and TIMESTAMPb b


5.Binary data types: store data exactly as the data appears in memory or c
b b b b b b b b b b b b b

omputer files, bit for bit b b b b

Common binary data types: BLOB, BINARY, VARBINARY, and IMAGE
b b b b b b b b

6. Spatial data types: store geometric information, such as lines, polygon
b b b b b b b b b

s, and map coordinates.
b b b


7. Document data types: contain textual data in a structured format such a
b b b b b b b b b b b

s XML or JSON
b b b


8. FLOAT: common decimal binary type that represents numbers with f
b b b b b b b b b

ractional values. b

9. BLOB: common binary data type that stores data in binary form (0s and
b b b b b b b b b b b b

1s)
10.TIMESTAMP: includes time zone. b b b

11.Structural rule: -Tables are normalized — b b b b b

exactly one value exists in each cell
b b b b b b b

-
no duplicate column names allowed. Same column name can appear in a
b b b b b b b b b b b b

different table. b

-no duplicate rows allowed in all columns.
b b b b b b

12. What does the principle of data independence state?
b b b b b b b




1) The performance of a query is not related to the physical organization of
b b b b b b b b b b b b b

data.
2) Data in each row is independent of data in all other rows.
b b b b b b b b b b b

3) The result of a database query is not affected by the physical organization
b b b b b b b b b b b b b

of data on storage devices.: The result of a database query is not affected b
b b b b b b b b b b b b b b

1b/b10

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13. How can driver's license information be added to the Employee table?
b b b b b b b b b b




1) Driver's licenses cannot be added, since the Employee table already has an
b b b b b b b b b b b

bID column.
b

2) By creating another column named ID.
b b b b b

3) By creating another column with a new name, such as ID2 or DriverLicense.
b b b b b b b b b b b b


: By creating another column with a new name, such as ID2 or DriverLic
b b b b b b b b b b b b b

ense. (note: A table may have several columns with similar information
b b b b b b b b b b

, as long as the column names are different.)
b b b b b b b b


14.NULL: special value that represents missing data (unknown or inapp
b b b b b b b b b

licable.) Note: zero is not same as NULL since it is still applicable.
b b b b b b b b b b b b




2b/b10

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15.Some columns should never contain a NULL. What does this mean?: the
b b b b b b b b b b b

ID column identifies employees and should always have a valid integer
b b b b b b b b b b b b

value and therefore NULL cannot be present here.
b b b b b b b


16.NOT NULL: To prohibit NULL, a column can be designated NOT NULL in
b b b b b b b b b b b b b

SQL. The database rejects any attempt to insert a row with missing data i
b b b b b b b b b b b b b

n a NOT NULL column.
b b b b

17. What does a NULL in the Name column present? b b b b b b b b




1) Unknown
2) Inapplicable
3) Either unknown or inapplicable: Unknown. b b b b

(note: Every employee has a name, so NULL indicates the name exists but
b b b b b b b b b b b b

bhas not been entered. The name is unknown to the database.)
b b b b b b b b b b

18. In the Bonus column of the Lisa Ellison row, what does the zero represent
b b b b b b b b b b b b b

?

1) Lisa Ellison's bonus is unknown. b b b b

2) Lisa Ellison is not eligible for a bonus.
b b b b b b b

3) Lisa Ellison has earned no bonus.: Lisa Ellison has earned no onus
b b b b b b b b b b b b

(note: Zero is a valid bonus amount. Zero is not the same as unknown
b . or in
b b b b b b b b b b b b b b

applicable data.) b


19. If the Department column is designated NOT NULL, what happens when a
b b b b b b b b b b b

buser attempts to insert a new employee without a department value?
b b b b b b b b b b




1) The database accepts the insert and stores a blank string as the Departmen
b b b b b b b b b b b b

t name. b

2) The database accepts the insert and saves NULL in the column.
b b b b b b b b b b

3) The database rejects the insert.: The database rejects the insert.
b b b b b b b b b

(note: A database does not accept an insert with missing Department data
b b b b b b b b b b b

. The insert statement fails.)
b b b b

20.SUM: Aggregate function which returns the total of selected values.
b b b b b b b b b

21.AVG: aggregate function that returns the average of selected values.
b b b b b b b b b

22.MAX: returns the largest selected value. b b b b b

23.MIN: returns the smallest selected value. b b b b b

(note: SUM, AVG, MIN, and MAX ignore NULL values.)
b b b b b b b b


24.When SELECT MAX (Salary + Bonus) from the compensation ptable in the
b b b b b b b b b b b b


icture,: Salary + bonus is NULL for Lisa Ellison and Jiho Chen, so AX ignores
b b b b b b b b b b b b b


bM these rows. MAX selects the largest amount from the remain s. So, 900
b b b b b b b b b b b b b


ing two row b b 00
3b/b10