WorksheetsInformation Management Midterm Exam
Total questions: 30
Worksheet time: 15mins
What is the primary purpose of an index in a database?
To increase storage space
To slow down data retrieval
To map data for faster retrieval
To delete data
Which of the following is NOT a type of index?
B-tree index
Hash index
Bitmap index
Array index
In SQL, which statement is used to create an index?
SELECT INDEX
CREATE INDEX
INSERT INDEX
UPDATE INDEX
What happens when a query with a WHERE clause is executed on a table without an index?
The database uses binary search to find matching rows
The database engine scans the entire table row by row
The query is automatically optimized without any index
The database engine ignores the WHERE clause
If you frequently use two columns in the WHERE clause of a query, which type of index would be the most efficient?
Single-column index
Composite index
No index
Full-text index
Which component of an index contains the actual data references?
Search Key
Data Reference
Hash Key
Index Key
How does the buffer manager in DBMS handle data blocks when there is no space left in the buffer?
It immediately crashes
It removes older blocks and writes updated blocks to disk
It ignores new data requests
It duplicates existing data blocks
What is the role of a web crawler in the context of web indexing?
To block all access to websites
To store webpages permanently
To systematically browse and index web pages
To optimize database storage
What is the main trade-off when creating multiple indexes on a table?
Improved performance and reduced maintenance
Faster data retrieval but increased disk space usage and slower modification operations
Slower retrieval times but better data accuracy
Reduced storage but faster index creation
In buffer management, why is it necessary to carefully allocate space for database buffers in main memory?
Because the main memory has unlimited space
To ensure that all data can always be accessed from disk
To minimize the number of transfers between disk storage and main memory
To increase the frequency of disk accesses
What is a relational database?
A system for managing social media posts
A digital spreadsheet for managing calculations
A digital filing cabinet for storing and organizing connected data
A program for sending emails
Which key uniquely identifies each record in a relational database table?
Foreign key
Composite key
Primary key
Alternate key
What ensures that the foreign key value exists in the referenced table's primary key?
Referential integrity
Entity integrity
Redundancy
Normalization
Which process organizes data into a structure that eliminates redundancies in a database?
Denormalization
Normalization
Indexing
Aggregation
In a table with attributes (Employee_ID, Employee_Name, Employee_Department), which attribute is functionally dependent on Employee_ID?
Employee_Department
Employee_Name
Both Employee_Name and Employee_Department
None
Which SQL operation is commonly used to link tables together by their foreign and primary keys?
Union
Join
Select
Aggregate
Which of the following represents a multi-valued dependency?
A student can enroll in multiple courses, and each course can be taught by multiple instructors
A customer places only one order at a time
Each product has a unique SKU number
An employee belongs to a single department
Which normal form deals with removing multi-valued dependencies in a database?
First Normal Form (1NF)
Third Normal Form (3NF)
Fourth Normal Form (4NF)
Boyce-Codd Normal Form (BCNF)
Which property ensures that a decomposition of a schema does not lose any information when joined back together?
Dependency-preservation
Lossless-join
Transitivity
Closure
In Boyce-Codd Normal Form (BCNF), which condition must be met?
Every non-key attribute must depend on the whole primary key
Every determinant must be a candidate key
There must be no transitive dependencies
Each table must have a foreign key
What is a database?
A collection of unrelated data
A collection of organized data that users can access electronically
A single table of records
A programming language
Which of the following is a sublanguage in SQL?
Data Construction Language
Data Definition Language
Data Aggregation Language
Data Query Language
What does SQL stand for?
Simple Query Language
Structured Query Language
Script Query Language
System Query Language
Which SQL statement is used to update existing data in a table?
UPDATE
INSERT
DELETE
CREATE
Which of the following SQL functions is used to retrieve records that match multiple conditions?
SELECT
UPDATE
WHERE AND
INSERT
What is the role of the SELECT statement in SQL?
To delete data from a database
To extract data from a database
To update records in a table
To define a database schema
Which command is used to remove records from a table in SQL?
UPDATE
INSERT
DELETE
SELECT
What is the purpose of the WHERE clause in SQL?
It defines the structure of a table
It specifies the columns to be retrieved
It is used to filter records that meet specific criteria
It updates the data in a table
Which of the following best describes a "projection" operation in SQL?
Retrieving rows from a table based on conditions
Selecting specific columns from a table while ignoring others
Combining data from multiple tables using a common key
Grouping data by one or more columns and applying aggregate functions
Which SQL sequence is used to combine data from multiple tables based on a common column or key?
Select-Project-Join
Group By-Order By
Aggregate-Filter-Join
Union-All
