WGU C175 (D426) DATA MANAGEMENT
1. What does modality refer to? How does it appear on an ER diagram?
a. Refers to the MINIMUM number of times an instance in one entity can be
associated with instance of another entity(minima). Appears as a 0 or 1 on
the relationship line, next to cardinality.
2. Define: Referential Integrity
a. Requires that ALL foreign key values must either be fully NULL or match
some primary key.
3. Four ways Referential Integrity can be violated:
a. Primary key is updated
b. Foreign key is updated
c. Row containing primary key is deleted
d. Row containing foreign key is inserted
4. Actions to Correct Referential Integrity Violation:
a. RESTRICT – rejects an insert, update or delete
b. SET NULL – sets invalid foreign keys to null
c. SET DEFAULT – sets invalid foreign keys to a default primary value
d. CASCADE – propagates primary key changes to foreign keys
5. What is an important aspect to referential integrity?
a. Reference to data in one relation is based on values in another relation.
6. What is a broad definition of data?
a. Raw facts captured or printed on digital media.
,7. What are data?
a. Facts that are collection and stored in a database system.
8. What is a determining characteristic of unstructured data?
a. It does not follow a data model.
9. What is true about flat files?
a. They contain no internal hierarchical organization.
10. How were data retrieved before database management systems?
a. Sequentially from simple files
11. What is an attribute or group of attributes that uniquely identify a tuple
in a relation?
a. Primary Key
12. What is necessary for a primary key in one relation of a database to
match with its corresponding foreign key in another relation to the same
database?
a. A domain of values
13. What uniquely identifies each entity in a collection of entities bus is not
the primary key?
a. Alternate Key
14. What is the term for a set of columns in a table that can uniquely identify
and record in that table without referring to other data?
, a. Candidate Key
15. What happens to the original data in the database indexing?
a. It is copied to the index
16. Why are indexes created in a physical database design?
a. To retrieve data DIRECTLY using a pointer
17. Why is an index created on a database column?
a. To optimize data retrievals
18. Define Functional Dependency:
a. Each value of a column relates to at MOST one value of another column.
Dependence of one column on another
19. What term is used to describe: a value of one particular attribute
associated with a specific single value of another attribute?
a. Functional Dependency
20. Rules / Appearance of First Nominal Form:
a. All non-key columns depend on the whole primary key.
b. Each table cell contains one value.
c. A table with no duplicate rows.
Must be in 1NF - Non-key column cannot depend on just one part of a
composite key - a single primary key is automatically in 2NF
1. What does modality refer to? How does it appear on an ER diagram?
a. Refers to the MINIMUM number of times an instance in one entity can be
associated with instance of another entity(minima). Appears as a 0 or 1 on
the relationship line, next to cardinality.
2. Define: Referential Integrity
a. Requires that ALL foreign key values must either be fully NULL or match
some primary key.
3. Four ways Referential Integrity can be violated:
a. Primary key is updated
b. Foreign key is updated
c. Row containing primary key is deleted
d. Row containing foreign key is inserted
4. Actions to Correct Referential Integrity Violation:
a. RESTRICT – rejects an insert, update or delete
b. SET NULL – sets invalid foreign keys to null
c. SET DEFAULT – sets invalid foreign keys to a default primary value
d. CASCADE – propagates primary key changes to foreign keys
5. What is an important aspect to referential integrity?
a. Reference to data in one relation is based on values in another relation.
6. What is a broad definition of data?
a. Raw facts captured or printed on digital media.
,7. What are data?
a. Facts that are collection and stored in a database system.
8. What is a determining characteristic of unstructured data?
a. It does not follow a data model.
9. What is true about flat files?
a. They contain no internal hierarchical organization.
10. How were data retrieved before database management systems?
a. Sequentially from simple files
11. What is an attribute or group of attributes that uniquely identify a tuple
in a relation?
a. Primary Key
12. What is necessary for a primary key in one relation of a database to
match with its corresponding foreign key in another relation to the same
database?
a. A domain of values
13. What uniquely identifies each entity in a collection of entities bus is not
the primary key?
a. Alternate Key
14. What is the term for a set of columns in a table that can uniquely identify
and record in that table without referring to other data?
, a. Candidate Key
15. What happens to the original data in the database indexing?
a. It is copied to the index
16. Why are indexes created in a physical database design?
a. To retrieve data DIRECTLY using a pointer
17. Why is an index created on a database column?
a. To optimize data retrievals
18. Define Functional Dependency:
a. Each value of a column relates to at MOST one value of another column.
Dependence of one column on another
19. What term is used to describe: a value of one particular attribute
associated with a specific single value of another attribute?
a. Functional Dependency
20. Rules / Appearance of First Nominal Form:
a. All non-key columns depend on the whole primary key.
b. Each table cell contains one value.
c. A table with no duplicate rows.
Must be in 1NF - Non-key column cannot depend on just one part of a
composite key - a single primary key is automatically in 2NF
