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IM Handout 3 - Midterm Flashcards | StudBud
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IM Handout 3 - Midterm
IM Handout 3 - Midterm
30 terms
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Questions
30
Answers
1
What is the condition to be evaluated in relational algebra called?
Closure
Domain
Predicate
Determinant
2
What does the JOIN operator do?
Retrieves a subset of columns
Retrieves rows based on common values in attributes
Retrieves rows common to two tables
Retrieves rows from one table not found in another
3
What does each row in a table represent?
Tuple
Domain
Key
Attribute
4
What happens if a primary key is deleted while it has matching foreign key values in another table?
The table is deleted
The deletion is blocked to maintain referential integrity
The foreign key values are automatically updated
The foreign key values are set to null
5
What is the result of applying relational algebra operators on existing tables called?
Determinant
Domain
Predicate
Closure
6
What is relational algebra?
A method for defining integrity rules
A set of mathematical principles for manipulating table contents
A method for encrypting data
A way to create new tables
7
Which of the following is an example of referential integrity?
STU_LNAME is unique
STU_NUM is unique and non-null
STU_SECT matches a primary key in another table
STU_FNAME is non-null
8
Who introduced the relational model in 1970?
Bill Gates
Edgar F. Codd
Charles Bachman
Larry Ellison
9
Which operator retrieves possible pairs of rows from two tables?
PRODUCT
UNION
JOIN
INTERSECT
10
Which of the following is true about union-compatible tables?
They have the same primary key
They have the same foreign key
They have the same number of rows
They have the same number of columns and compatible domains
11
Which operator retrieves rows common to two tables?
INTERSECT
PRODUCT
UNION
DIFFERENCE
12
Which of the following is true about the order of rows and columns in a relational database?
The order of rows is important, but columns are not.
The order of columns is important, but rows are not.
Neither the order of rows nor columns is important.
Both the order of rows and columns are important.
13
Which of the following is an example of a composite key?
STU_SECT
STU_LNAME
STU_NUM
(STU_NUM, STU_LNAME)
14
Which of the following is a requirement for entity integrity?
Primary key entries must be unique and non-null
Tables must be union-compatible
Foreign keys must match primary keys
All attributes must have values
15
What is referential integrity?
Ensuring that all attributes have values
Ensuring that each row has a unique identity
Ensuring that foreign keys match primary keys or are null
Ensuring that tables are union-compatible
16
What does the DIFFERENCE operator do?
Retrieves rows from one table not found in another
Merges two tables and drops duplicate rows
Retrieves possible pairs of rows from two tables
Retrieves rows common to two tables
17
What is the term for the range of values that a column can contain?
Tuple
Key
Attribute
Domain
18
In the relational model, a table is also known as a ________
Attribute
Domain
Relation
Tuple
19
What is entity integrity?
Ensuring that all attributes have values
Ensuring that tables are union-compatible
Ensuring that each row has a unique identity
Ensuring that foreign keys match primary keys
20
What is a superkey?
A key that can contain null values
A key that is composed of multiple attributes
A key that uniquely identifies any row in the table
A key that is used for data retrieval only
21
What is a key in a relational database?
A unique identifier for a table
An attribute that determines the values of other attributes
A combination of rows and columns
A mathematical operation on tables
22
Which operator retrieves a subset of columns from a table?
SELECT
JOIN
UNION
PROJECT
23
Which of the following is an example of a foreign key?
STU_SECT
STU_FNAME
STU_NUM
STU_LNAME
24
Which of the following is a candidate key?
STU_LNAME
STU_SECT
STU_MI
STU_NUM
25
What is the purpose of a secondary key?
To uniquely identify a row
To enforce referential integrity
To retrieve data
To link tables
26
What is the determinant in the relationship STU_NUM → STU_LNAME?
STU_SECT
STU_LNAME
STU_NUM
STU_FNAME
27
What does the UNION operator do?
Merges two tables and drops duplicate rows
Retrieves rows common to two tables
Retrieves rows from one table not found in another
Retrieves possible pairs of rows from two tables
28
What is the purpose of the DIVIDE operator in relational algebra?
To retrieve values that match a specific condition
To retrieve rows from one table not found in another
To retrieve a subset of columns
To retrieve rows based on common values
29
Which operator retrieves a subset of rows from a table?
SELECT
PROJECT
JOIN
UNION
30
Which of the following is NOT a component of the relational model?
Data manipulation operations
Integrity rules
Data encryption
Logical data structure
