WGU D426/427
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1. What is a subquery A query within another SQL query.
2. What is an alias in SQL A temporary name assigned to a column or table, created with
the AS keyword.
3. What is a materialized view A view for which data is stored at all times and must be re-
freshed when the base table changes.
4. What does the WITH CHECK Ensures that inserts and updates in a view satisfy the view's
OPTION clause do WHERE clause.
5. What is an entity in entity-rela- A person, place, product, concept, or activity.
tionship modeling
6. What is a relationship in enti- A statement about two entities.
ty-relationship modeling
7. What is an attribute in enti- A descriptive property of an entity.
ty-relationship modeling
8. What is a reflexive relationship A relationship that relates an entity to itself.
9. What is an entity-relationship A schematic picture of entities, relationships, and attributes,
diagram (ER diagram) where entities are drawn as rectangles.
10. What is an entity type A set of things, such as all employees in a company.
11. What is a relationship type A set of related things, such as employee-manages-depart-
ment pairs.
12. What is an attribute type A set of values, such as all employee salaries.
13. What is an entity instance An individual thing, such as the employee Sam Snead.
14. What is a relationship instance
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, WGU D426 427
WGU D426/427
Study online at https://quizlet.com/_fkm96x
A specific statement about entity instances, such as "Maria
Rodriguez manages Sales."
15. What is an attribute instance An individual value, such as a salary of $35,000.
16. What is cardinality in entity-re- The maxima and minima of relationships and attributes.
lationship modeling
17. What is a subtype entity A subset of another entity type, called the supertype entity.
18. What is a supertype entity An entity that has one or more subtype entities, such as "vehi-
cle" with subtypes like "car" and "truck."
19. What is an IsA relationship The identifying relationship between a supertype and its sub-
types.
20. What is a partition in entity-re- A group of mutually exclusive subtype entities within a super-
lationship modeling type entity.
21. What is crow's foot notation A convention for depicting cardinality in ER diagrams, using
symbols like circles, short lines, and three short lines (a crow's
foot).
22. What is an intangible entity An entity documented in the data model but not tracked with
data in the database.
23. What are the characteristics of A primary key should be stable, simple, and meaningless.
a primary key
24. What is an artificial key A single-column primary key created by the database designer
when no suitable primary key exists.
25. What is functional dependence The dependence of one column on another.
26. The repetition of related values in a table.
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