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Unit 5: Introduction to PostgreSQL - Practice Quiz

INT222 — Advanced Web Development 50 Questions
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1 What type of database management system is PostgreSQL classified as?

A. Flat File Database
B. Object-Relational Database Management System (ORDBMS)
C. Hierarchical Database
D. Network Database

2 Which mechanism does PostgreSQL use to handle concurrency without read locks blocking write locks?

A. Table Locking
B. Two-Phase Locking
C. MVCC (Multi-Version Concurrency Control)
D. Optimistic Locking

3 What is the default TCP port that PostgreSQL listens on?

A. 8080
B. 3306
C. 5432
D. 1521

4 What is the name of the interactive terminal-based command-line tool for PostgreSQL?

A. sqlcmd
B. pgAdmin
C. psql
D. pg_terminal

5 Which configuration file is primarily responsible for controlling client authentication in PostgreSQL?

A. config.json
B. pg_hba.conf
C. postgresql.conf
D. pg_ident.conf

6 What is the default superuser account created during PostgreSQL installation?

A. sa
B. postgres
C. admin
D. root

7 Which command inside the psql interface is used to list all databases?

A. \l
B. SHOW DATABASES;
C. \list
D. Both A and B

8 Which data type in PostgreSQL is best suited for storing JSON data with indexing capabilities?

A. JSONB
B. VARCHAR
C. TEXT
D. JSON

9 Which SQL statement is used to create a new database in PostgreSQL?

A. CREATE DATABASE name;
B. NEW DATABASE name;
C. MAKE DATABASE name;
D. INIT DATABASE name;

10 What does the acronym WAL stand for in the context of PostgreSQL architecture?

A. Wide-Area Latency
B. Web Application Layer
C. Write-Ahead Logging
D. Write-After Log

11 Which command allows you to connect to a specific database from within the psql prompt?

A. \connect dbname
B. \use dbname
C. \c dbname
D. Both A and B

12 To remove a table and all its data from the database, which command is used?

A. DELETE TABLE
B. ERASE TABLE
C. DROP TABLE
D. REMOVE TABLE

13 Which PostgreSQL data type is an auto-incrementing integer typically used for primary keys?

A. NUMERIC
B. INT
C. AUTO_INT
D. SERIAL

14 What is the purpose of the 'TRUNCATE' command?

A. To delete specific rows based on a condition
B. To drop the table structure
C. To minify the database size
D. To delete all rows quickly without logging individual row deletions

15 Which constraint ensures that a column cannot contain NULL values?

A. PRIMARY KEY
B. NOT NULL
C. UNIQUE
D. CHECK

16 How do you rename an existing table 'users' to 'customers' in PostgreSQL?

A. MODIFY TABLE users RENAME customers;
B. UPDATE TABLE users SET NAME = customers;
C. ALTER TABLE users RENAME TO customers;
D. RENAME TABLE users TO customers;

17 Which operator is used for pattern matching with wildcards in a WHERE clause?

A. MATCH
B. LIKE
C. SAME
D. =

18 In the context of the LIKE operator, what does the '%' wildcard represent?

A. A NULL value
B. Zero or more characters
C. A numeric digit
D. Exactly one character

19 Which SQL clause is used to filter records that meet a specified condition?

A. ORDER BY
B. HAVING
C. GROUP BY
D. WHERE

20 What is the correct syntax to insert a new record into the 'students' table?

A. ADD TO students VALUES (1, 'John');
B. INSERT students SET id=1, name='John';
C. INSERT INTO students (id, name) VALUES (1, 'John');
D. UPDATE students ADD (1, 'John');

21 How can you retrieve all columns from the 'employees' table?

A. FETCH employees;
B. SELECT * FROM employees;
C. SELECT ALL FROM employees;
D. GET * FROM employees;

22 Which clause allows you to limit the number of rows returned by a query?

A. STOP
B. TOP
C. LIMIT
D. ROWNUM

23 Which command allows you to skip a specific number of rows before returning the result set?

A. NEXT
B. SKIP
C. OFFSET
D. JUMP

24 What is the correct syntax to update the email of a user with id 5?

A. SET users.email = 'new@test.com' WHERE id = 5;
B. MODIFY users SET email = 'new@test.com' WHERE id = 5;
C. UPDATE users SET email = 'new@test.com' WHERE id = 5;
D. CHANGE users email = 'new@test.com' WHERE id = 5;

25 What happens if you run a DELETE FROM table_name command without a WHERE clause?

A. It deletes the table structure.
B. It throws a syntax error.
C. It deletes the first row.
D. It deletes all rows in the table.

26 Which keyword is used to return data immediately after an INSERT, UPDATE, or DELETE operation in PostgreSQL?

A. BACK
B. RETURNING
C. RETURN
D. OUTPUT

27 Which PostgreSQL data type stores both date and time?

A. TIMESTAMP
B. DATE
C. DATETIME
D. TIME

28 Which command is used to modify the structure of an existing table, such as adding a column?

A. MODIFY TABLE
B. ALTER TABLE
C. UPDATE TABLE
D. CHANGE TABLE

29 To ensure a column's value is unique across the entire table, which constraint should be used?

A. UNIQUE
B. DISTINCT
C. SINGLE
D. PRIMARY

30 Which operator is used to combine string values in PostgreSQL?

A. +
B. &
C. ||
D. CONCAT()

31 How do you sort the result set in descending order?

A. SORT BY column_name DESC
B. ORDER BY column_name DESC
C. GROUP BY column_name DESC
D. ORDER BY column_name ASC

32 Which function is used to count the number of rows in a selection?

A. TOTAL()
B. SUM()
C. COUNT()
D. ADD()

33 What is the purpose of the DISTINCT keyword in a SELECT statement?

A. To limit results
B. To filter null values
C. To remove duplicate values from the result set
D. To sort results

34 Which of the following is a correct command to add a new column 'age' of type integer to table 'people'?

A. UPDATE TABLE people ADD age INTEGER;
B. INSERT COLUMN age INTEGER INTO people;
C. ALTER people ADD age INTEGER;
D. ALTER TABLE people ADD COLUMN age INTEGER;

35 What does the psql command '\d table_name' do?

A. Downloads the table
B. Duplicates the table
C. Describes the table structure
D. Deletes the table

36 Which logical operator is used to display a record if any of the conditions separated by it are true?

A. XOR
B. AND
C. OR
D. NOT

37 How do you check for a NULL value in a WHERE clause?

A. IS NULL
B. == NULL
C. = NULL
D. EQUALS NULL

38 Which PostgreSQL tool is a popular open-source GUI for database management?

A. pgAdmin
B. Workbench
C. Compass
D. phpMyAdmin

39 What does the PRIMARY KEY constraint imply?

A. Both UNIQUE and NOT NULL
B. Just an index
C. NOT NULL only
D. UNIQUE only

40 Which command allows you to quit the psql terminal?

A. logout
B. exit
C. \q
D. quit

41 Which clause is used to filter groups of rows created by GROUP BY?

A. FILTER
B. LIMIT
C. WHERE
D. HAVING

42 Which statement is used to delete an entire database?

A. DROP DATABASE name;
B. REMOVE DATABASE name;
C. TRUNCATE DATABASE name;
D. DELETE DATABASE name;

43 What is the purpose of the 'IN' operator?

A. To specify a range
B. To specify multiple possible values for a column
C. To search text patterns
D. To check for NULL

44 Which data type would be most appropriate for a True/False value?

A. INT
B. BINARY
C. BOOLEAN
D. VARCHAR(1)

45 What does the BETWEEN operator select?

A. Values within a given range
B. Values that match a list
C. Values that are distinct
D. Values that are null

46 To create a foreign key, which table is modified?

A. The child table
B. The parent table
C. Both tables
D. The system table

47 Which command is used to remove a specific column from a table?

A. ALTER TABLE ... DROP COLUMN ...
B. ALTER TABLE ... REMOVE COLUMN ...
C. ALTER TABLE ... DELETE COLUMN ...
D. DROP COLUMN ... FROM ...

48 Which basic SQL command is NOT part of CRUD operations?

A. CREATE
B. INSERT
C. UPDATE
D. SELECT

49 What is the default sort order if ASC or DESC is not specified in ORDER BY?

A. Descending
B. Random
C. Ascending
D. Insertion Order

50 Which character is used to denote a parameter/variable placeholder in a prepared statement in psql (e.g., $1, $2)?

A. @
B. $
C. :
D. ?
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