KDB+ MCQs and Answers with Explanation | KDB+ Quiz

KDB+ MCQs and Answers with Explanation: This article presents a valuable resource for anyone looking to improve their understanding and skills in KDB+. The KDB+ MCQs with answers/ KDB+ Quiz will help aspirants gain immense knowledge about this concept. KDB+ is a powerful database and analytics platform designed for high-performance computing, data management, and analysis. Developed by Kx Systems, it is widely used in finance, telecommunications, and other industries that require real-time data processing and analysis. KDB+ has a unique architecture that enables it to handle massive amounts of data with exceptional speed and efficiency. It is a popular choice for high-frequency trading, risk management, and other applications where speed and accuracy are critical.

KDB+ MCQs with Answers

This article provides a collection of KDB+ Multiple Choice Questions (MCQs) with answers to help you test and enhance your knowledge of this powerful database technology. Whether you are a beginner or an experienced user, these Top 53 KDB+ MCQ Questions will challenge you and deepen your understanding of KDB+.

KDB+ Multiple Choice Questions

Name	KDB+
Exam Type	MCQ (Multiple Choice Questions)
Category	Technical Quiz
Mode of Quiz	Online

Top 53 KDB+ Multiple Choice Questions | KDB+ Quiz

1. What is KDB+?

A) A programming language for database management
B) A database management system
C) An operating system
D) A machine learning library

Answer: B) A database management system

Explanation: KDB+ is a high-performance column-oriented database management system. It is used for handling large and complex data sets in real-time applications.

2. What is the maximum number of columns that can be stored in a KDB+ table?

A) 1024
B) 2048
C) 4096
D) 8192

Answer: D) 8192

Explanation: KDB+ can store up to 8192 columns in a single table. This makes it suitable for handling complex and wide data sets.

3. Which of the following is a valid data type in KDB+?

A) String
B) Double
C) Long
D) All of the above

Answer: D) All of the above

Explanation: KDB+ supports various data types, including strings, doubles, and longs. It also supports other data types such as symbols, timestamps, and GUIDs.

4. What is a tick data in KDB+?

A) Data that is stored in a table with one row for each transaction
B) Data that is stored in a table with one column for each transaction
C) Data that is stored in a table with one row for each time period
D) Data that is stored in a table with one column for each time period

Answer: A) Data that is stored in a table with one row for each transaction

Explanation: In KDB+, tick data is stored in a table with one row for each transaction or tick. Each row represents a specific transaction, and each column contains the relevant information about that transaction.

5. Which of the following is a valid way to create a KDB+ table?

A) Using the CREATE TABLE statement
B) Using the INSERT INTO statement
C) Using the LOAD statement
D) Using the SELECT statement

Answer: C) Using the LOAD statement

Explanation: The LOAD statement is used to create a KDB+ table from a flat file. The file should be in a specific format that can be read by KDB+. Alternatively, tables can also be created using the qSQL language, which is similar to SQL.

6. What is the difference between a keyed and unkeyed table in KDB+?

A) Keyed tables are sorted based on a specific column, while unkeyed tables are not
B) Keyed tables contain a primary key column, while unkeyed tables do not
C) Keyed tables can be accessed faster than unkeyed tables
D) There is no difference between keyed and unkeyed tables

Answer: B) Keyed tables contain a primary key column, while unkeyed tables do not

Explanation: In KDB+, a keyed table is a table that has a primary key column. This column is used to sort and index the table, which allows for faster access to the datA) Unkeyed tables, on the other hand, do not have a primary key column and are not sorted or indexeD)

7. Which of the following is a valid way to select data from a KDB+ table?

A) Using the SELECT statement
B) Using the WHERE clause
C) Using the GROUP BY clause
D) All of the above

Answer: D) All of the above

Explanation: KDB+ supports a variety of SQL-like syntax for selecting data from tables, including the SELECT statement, WHERE clause, and GROUP BY clause. These statements are used to filter, group, and aggregate data in a table.

8. Which of the following is not a valid aggregation function in KDB+?

A) AVG
B) SUM
C) MAX
D) PRODUCT

Answer: D) PRODUCT

Explanation: While KDB+ supports aggregation functions like AVG, SUM, and MAX, it does not support the PRODUCT function for aggregating datA)

9. Which of the following is not a valid way to sort data in a KDB+ table?

A) Using the ORDER BY clause
B) Using the ASC keyword
C) Using the DESC keyword
D) Using the SORT function

Answer: D) Using the SORT function

Explanation: While the SORT function can be used to sort data in KDB+, it is not a valid way to sort data in a table. The ORDER BY clause and ASC/DESC keywords are used to sort data in a table.

10. What is the syntax for creating a new column in a KDB+ table?

A) ALTER TABLE table_name ADD COLUMN column_name data_type
B) UPDATE table_name SET column_name = value
C) INSERT INTO table_name (column_name) VALUES (value)
D) None of the above

Answer: A) ALTER TABLE table_name ADD COLUMN column_name data_type

Explanation: To create a new column in a KDB+ table, the ALTER TABLE statement is used with the ADD COLUMN clause. The statement should specify the table name, the name of the new column, and the data type of the column.

11. Which of the following is a valid way to join two KDB+ tables?

A) Using the INNER JOIN clause
B) Using the OUTER JOIN clause
C) Using the UNION clause
D) KDB+ does not support table joins

Answer: D) KDB+ does not support table joins

Explanation: Unlike traditional SQL databases, KDB+ does not support table joins. Instead, it uses a different data model that is optimized for handling large and complex data sets.

12. What is the maximum size of a KDB+ database file?

A) 1 GB
B) 10 GB
C) 100 GB
D) There is no maximum size

Answer: D) There is no maximum size

Explanation: KDB+ can handle very large databases, and there is no specific maximum size limit for a KDB+ database file. The limit is usually determined by the available disk space on the system.

13. Which of the following is a valid way to delete data from a KDB+ table?

A) Using the DELETE statement
B) Using the DROP statement
C) Using the TRUNCATE statement
D) All of the above

Answer: A) Using the DELETE statement

Explanation: The DELETE statement is used to remove specific rows from a KDB+ table. The DROP statement is used to remove an entire table, while the TRUNCATE statement is used to remove all data from a table.

14. Which of the following is not a valid way to backup a KDB+ database?

A) Copying the database file to a different location
B) Using the BACKUP command
C) Using a database replication tool
D) There is no need to backup a KDB+ database

Answer: D) There is no need to backup a KDB+ database

Explanation: It is important to backup a KDB+ database, just like any other database management system. Copying the database file to a different location, using the BACKUP command, or using a database replication tool are all valid ways to backup a KDB+ database.

15. Which of the following is a valid way to execute a KDB+ script?

A) Using the q interpreter
B) Using the q compiler
C) Using the q IDE
D) All of the above

Answer: A) Using the q interpreter

Explanation: The q interpreter is the primary way to execute KDB+ scripts. The interpreter allows users to enter commands and scripts directly into the console, and it also provides support for various debugging and profiling tools.

16. Which of the following is a valid way to export data from a KDB+ table to a CSV file?

A) Using the .Q.csv function
B) Using the .Q.save function
C) Using the .Q.export function
D) KDB+ does not support exporting data to CSV files

Answer: A) Using the .Q.csv function

Explanation: The .Q.csv function is used to export data from a KDB+ table to a CSV file. The function should specify the name of the CSV file and the name of the table to export.

17. Which of the following is a valid way to plot data in KDB+?

A) Using the PLOT function
B) Using the qplot function
C) Using a third-party library like Matplotlib
D) KDB+ does not support data visualization

Answer: C) Using a third-party library like Matplotlib

Explanation: While KDB+ does not have built-in support for data visualization, users can use third-party libraries like Matplotlib to plot data from KDB+ tables.

18. What is the syntax for selecting specific columns from a KDB+ table?

A) SELECT column1, column2 FROM table_name
B) SELECT * FROM table_name
C) ALTER TABLE table_name ADD COLUMN column_name data_type
D) None of the above

Answer: A) SELECT column1, column2 FROM table_name

Explanation: To select specific columns from a KDB+ table, the SELECT statement is used with the names of the columns to be selecteD) The statement should also specify the name of the table to be querieD)

19. Which of the following is a valid way to filter data in a KDB+ table?

A) Using the WHERE clause
B) Using the HAVING clause
C) Using the LIMIT clause
D) None of the above

Answer: A) Using the WHERE clause

Explanation: The WHERE clause is used to filter data in a KDB+ table based on a specific condition. The HAVING clause is used for filtering results from group functions, and the LIMIT clause is used to limit the number of results returneD)

20. What is the syntax for aggregating data in a KDB+ table?

A) SELECT AVG(column_name) FROM table_name
B) SELECT SUM(column_name) FROM table_name
C) SELECT MAX(column_name) FROM table_name
D) All of the above

Answer: D) All of the above

Explanation: To aggregate data in a KDB+ table, the SELECT statement is used with one of the aggregate functions like AVG, SUM, or MAX. The statement should also specify the name of the table to be queried and the name of the column to be aggregateD)

21. What is the syntax for updating data in a KDB+ table?

A) UPDATE table_name SET column_name = value WHERE condition
B) ALTER TABLE table_name ADD COLUMN column_name data_type
C) INSERT INTO table_name (column1, column2) VALUES (value1, value2)
D) None of the above

Answer: A) UPDATE table_name SET column_name = value WHERE condition

Explanation: To update data in a KDB+ table, the UPDATE statement is used with the name of the table to be updated, the name of the column to be updated, the new value, and the condition to select which rows to update.

22. What is the syntax for deleting data from a KDB+ table?

A) DELETE FROM table_name WHERE condition
B) DROP TABLE table_name
C) TRUNCATE TABLE table_name
D) None of the above

Answer: A) DELETE FROM table_name WHERE condition

Explanation: To delete data from a KDB+ table, the DELETE statement is used with the name of the table to be updated and the condition to select which rows to delete.

23. What is the difference between a KDB+ list and a KDB+ table?

A) A list can contain multiple data types, while a table can only contain one data type
B) A list is a one-dimensional structure, while a table is a two-dimensional structure
C) A list is immutable, while a table is mutable
D) None of the above

Answer: B) A list is a one-dimensional structure, while a table is a two-dimensional structure

Explanation: A KDB+ list is a one-dimensional structure that can contain values of different data types. A KDB+ table is a two-dimensional structure that consists of rows and columns, and each column can contain values of only one data type.

24. What is the difference between a KDB+ dictionary and a KDB+ table?

A) A dictionary is a one-dimensional structure, while a table is a two-dimensional structure
B) A dictionary can contain multiple data types, while a table can only contain one data type
C) A dictionary is a key-value mapping, while a table is a collection of columns
D) None of the above

Answer: C) A dictionary is a key-value mapping, while a table is a collection of columns

Explanation: A KDB+ dictionary is a collection of key-value pairs, where each key is associated with a corresponding value. In contrast, a KDB+ table is a collection of columns, where each column represents a different variable or attribute.

25. What is the syntax for creating a KDB+ dictionary?

A) dict([keys]; [values])
B) CREATE DICTIONARY dict_name (key_col data_type, value_col data_type)
C) CREATE TABLE dict_name (key_col data_type, value_col data_type)
D) None of the above

Answer: A) dict([keys]; [values])

Explanation: To create a KDB+ dictionary, the dict function can be used with two lists: one containing the keys and the other containing the corresponding values.

26. What is the syntax for adding a new key-value pair to a KDB+ dictionary?

A) dict_name[key] : value
B) INSERT INTO dict_name (key_col, value_col) VALUES (key, value)
C) ALTER DICTIONARY dict_name ADD KEY key VALUE value
D) None of the above

Answer: A) dict_name[key] : value

Explanation: To add a new key-value pair to a KDB+ dictionary, the square bracket syntax is used with the key and the colon operator is used to assign the corresponding value.

27. What is the syntax for retrieving the value associated with a specific key in a KDB+ dictionary?

A) dict_name[key]
B) SELECT value_col FROM dict_name WHERE key_col = key
C) GET dict_name key
D) None of the above

Answer: A) dict_name[key]

Explanation: To retrieve the value associated with a specific key in a KDB+ dictionary, the square bracket syntax is used with the key.

28. What is the difference between a KDB+ list and a KDB+ vector?

A) A list can contain values of different data types, while a vector can only contain values of one data type
B) A list is a one-dimensional structure, while a vector can be either one-dimensional or multi-dimensional
C) A list can be mutable or immutable, while a vector is always immutable
D) None of the above

Answer: B) A list is a one-dimensional structure, while a vector can be either one-dimensional or multi-dimensional

Explanation: A KDB+ list is a one-dimensional structure that can contain values of different data types. A KDB+ vector is a data structure that can be either one-dimensional or multi-dimensional, but all elements in a vector must be of the same data type.

29. What is the syntax for creating a KDB+ list?

A) list([values])
B) CREATE LIST list_name (data_type)
C) CREATE VECTOR list_name (data_type)
D) None of the above

Answer: A) list([values])

Explanation: To create a KDB+ list, the list function can be used with a list of values enclosed in square brackets.

30. What is the syntax for appending a new value to a KDB+ list?

A) list_name : value
B) list_name, value
C) APPEND list_name, value
D) None of the above

Answer: B) list_name, value

Explanation: To append a new value to a KDB+ list, the comma operator is used to separate the existing list from the new value.

31. What is the syntax for retrieving a specific element from a KDB+ list?

A) list_name[index]
B) SELECT * FROM list_name WHERE index_col = index
C) GET list_name index
D) None of the above

Answer: A) list_name[index]

Explanation: To retrieve a specific element from a KDB+ list, the square bracket syntax is used with the index of the desired element.

32. What is the syntax for creating a KDB+ vector?

A) vector([values])
B) CREATE VECTOR vector_name (data_type, shape)
C) CREATE TABLE vector_name (data_type, shape)
D) None of the above

Answer: B) CREATE VECTOR vector_name (data_type, shape)

Explanation: To create a KDB+ vector, the CREATE VECTOR statement is used with the data type and shape of the vector specifieD)

33. What is the syntax for retrieving a specific element from a KDB+ vector?

A) vector_name[index]
B) SELECT * FROM vector_name WHERE index_col = index
C) GET vector_name index
D) None of the above

Answer: A) vector_name[index]

Explanation: To retrieve a specific element from a KDB+ vector, the square bracket syntax is used with the index of the desired element.

34. What is the difference between a KDB+ list and a KDB+ array?

A) A list is a one-dimensional structure, while an array can be either one-dimensional or multi-dimensional
B) A list can contain values of different data types, while an array can only contain values of one data type
C) A list can be mutable or immutable, while an array is always immutable
D) None of the above

Answer: A) A list is a one-dimensional structure, while an array can be either one-dimensional or multi-dimensional

Explanation: A KDB+ list is a one-dimensional structure that can contain values of different data types. A KDB+ array is a data structure that can be either one-dimensional or multi-dimensional, and all elements in an array must be of the same data type.

35. What is the syntax for creating a KDB+ array?

A) array([values]; shape)
B) CREATE ARRAY array_name (data_type, shape)
C) CREATE TABLE array_name (data_type, shape)
D) None of the above

Answer: B) CREATE ARRAY array_name (data_type, shape)

Explanation: To create a KDB+ array, the CREATE ARRAY statement is used with the data type and shape of the array specifieD)

36. What is the syntax for retrieving a specific element from a KDB+ array?

A) array_name[index]
B) SELECT * FROM array_name WHERE index_col = index
C) GET array_name index
D) None of the above

Answer: A) array_name[index]

Explanation: To retrieve a specific element from a KDB+ array, the square bracket syntax is used with the index of the desired element.

37. What is the difference between a KDB+ vector and a KDB+ array?

A) A vector is a one-dimensional structure, while an array can be either one-dimensional or multi-dimensional
B) A vector can contain values of different data types, while an array can only contain values of one data type
C) A vector can be mutable or immutable, while an array is always immutable
D) None of the above

Answer: A) A vector is a one-dimensional structure, while an array can be either one-dimensional or multi-dimensional

Explanation: A KDB+ vector is a one-dimensional structure that can contain values of one data type. A KDB+ array is a data structure that can be either one-dimensional or multi-dimensional, and all elements in an array must be of the same data type.

38. What is the syntax for creating a KDB+ dictionary?

A) dictionary([keys]; [values])
B) CREATE DICTIONARY dict_name (key_type, value_type)
C) CREATE TABLE dict_name (key_type, value_type)
D) None of the above

Answer: B) CREATE DICTIONARY dict_name (key_type, value_type)

Explanation: To create a KDB+ dictionary, the CREATE DICTIONARY statement is used with the data types for the keys and values specifieD)

39. What is the syntax for adding a new key-value pair to a KDB+ dictionary?

A) dict_name[key] : value
B) dict_name[key] = value
C) INSERT INTO dict_name (key, value) VALUES (key_value, value_value)
D) None of the above

Answer: A) dict_name[key] : value

Explanation: To add a new key-value pair to a KDB+ dictionary, the colon operator is used to associate the key with the value.

40. What is the syntax for deleting a key-value pair from a KDB+ dictionary?

A) dict_name[key] : NULL
B) DELETE FROM dict_name WHERE key = key_value
C) REMOVE dict_name key
D) None of the above

Answer: A) dict_name[key] : NULL

Explanation: To delete a key-value pair from a KDB+ dictionary, the colon operator is used to assign a NULL value to the key.

41. What is the syntax for creating a KDB+ table?

A) CREATE TABLE table_name (col1_type, col2_type, …)
B) CREATE MATRIX table_name (row_type, col_type)
C) CREATE ARRAY table_name (data_type, shape)
D) None of the above

Answer: A) CREATE TABLE table_name (col1_type, col2_type, …)

Explanation: To create a KDB+ table, the CREATE TABLE statement is used with the data types for each column specifieD)

42. What is the syntax for inserting a new row into a KDB+ table?

A) INSERT INTO table_name (col1, col2, …) VALUES (value1, value2, …)
B) table_name[row] : (value1, value2, …)
C) APPEND table_name (value1, value2, …)
D) None of the above

Answer: A) INSERT INTO table_name (col1, col2, …) VALUES (value1, value2, …)

Explanation: To insert a new row into a KDB+ table, the INSERT INTO statement is used with the column names and values specifieD)

43. What is the syntax for updating a value in a KDB+ table?

A) UPDATE table_name SET col_name = new_value WHERE condition
B) table_name[row][col] : new_value
C) ALTER TABLE table_name MODIFY col_name new_data_type
D) None of the above

Answer: A) UPDATE table_name SET col_name = new_value WHERE condition

Explanation: To update a value in a KDB+ table, the UPDATE statement is used with the column name and new value specified, along with a condition to identify the row to be updateD)

44. What is the syntax for deleting a row from a KDB+ table?

A) DELETE FROM table_name WHERE condition
B) table_name[row] : NULL
C) DROP TABLE table_name
D) None of the above

Answer: A) DELETE FROM table_name WHERE condition

Explanation: To delete a row from a KDB+ table, the DELETE FROM statement is used with a condition to identify the row to be deleteD)

45. What is the syntax for joining two KDB+ tables?

A) table1 JOIN table2 ON condition
B) table1 UNION table2
C) table1 INTERSECT table2
D) None of the above

Answer: A) table1 JOIN table2 ON condition

Explanation: To join two KDB+ tables, the JOIN statement is used with the tables to be joined specified, along with a condition to specify how the tables are relateD)

46. What is the difference between a left join and a right join in KDB+?

A) A left join returns all rows from the left table and matching rows from the right table, while a right join returns all rows from the right table and matching rows from the left table
B) A left join returns all rows from both tables, while a right join returns only the matching rows from both tables
C) A left join returns only the matching rows from both tables, while a right join returns all rows from both tables
D) None of the above

Answer: A) A left join returns all rows from the left table and matching rows from the right table, while a right join returns all rows from the right table and matching rows from the left table

Explanation: In a left join, all rows from the left table are included in the result, along with any matching rows from the right table. In a right join, all rows from the right table are included in the result, along with any matching rows from the left table.

47. What is the syntax for aggregating data in KDB+?

A) SELECT agg_func(column) FROM table WHERE condition GROUP BY group_col
B) AGGREGATE table BY group_col INTO agg_col
C) COMPUTE agg_col := agg_func(column) BY group_col FROM table
D) None of the above

Answer: A) SELECT agg_func(column) FROM table WHERE condition GROUP BY group_col

Explanation: To aggregate data in KDB+, the SELECT statement is used with the aggregate function and column to be aggregated specified, along with a condition and a GROUP BY clause to specify how the data should be groupeD)

48. Which of the following is an example of an aggregate function in KDB+?

A) SUM
B) AVG
C) MAX
D) All of the above

Answer: D) All of the above

Explanation: SUM, AVG, and MAX are all examples of aggregate functions in KDB+. Other examples include MIN, COUNT, and MEDIAN.

49. What is the syntax for sorting data in KDB+?

A) SELECT * FROM table ORDER BY col ASC/DESC
B) SORT table BY col ASC/DESC
C) table[row] : SORT col ASC/DESC
D) None of the above

Answer: B) SORT table BY col ASC/DESC

Explanation: To sort data in KDB+, the SORT statement is used with the table and column to be sorted specified, along with either ASC or DESC to specify the sorting order.

50. What is the difference between ascending and descending order in KDB+ sorting?

A) Ascending order sorts the data in alphabetical order, while descending order sorts the data in reverse alphabetical order
B) Ascending order sorts the data from smallest to largest, while descending order sorts the data from largest to smallest
C) Ascending order sorts the data from oldest to newest, while descending order sorts the data from newest to oldest
D) None of the above

Answer: B) Ascending order sorts the data from smallest to largest, while descending order sorts the data from largest to smallest

Explanation: When sorting data in KDB+, ascending order sorts the data from smallest to largest, while descending order sorts the data from largest to smallest.

51. What is the syntax for limiting the number of rows returned in a KDB+ query?

A) SELECT * FROM table WHERE condition LIMIT num_rows
B) table[num_rows] : SELECT * FROM table WHERE condition
C) TOP num_rows FROM table WHERE condition
D) None of the above

Answer: C) TOP num_rows FROM table WHERE condition

Explanation: To limit the number of rows returned in a KDB+ query, the TOP statement is used with the number of rows to be returned specified, along with the table, condition, and any other relevant statements.

52. What is the difference between a scalar and a vector in KDB+?

A) A scalar is a single value, while a vector is a collection of values
B) A scalar is a collection of values, while a vector is a single value
C) A scalar is a numerical value, while a vector is a string value
D) None of the above

Answer: A) A scalar is a single value, while a vector is a collection of values

Explanation: In KDB+, a scalar is a single value, while a vector is a collection of values, which can be of any data type.

53. What is the syntax for creating a scalar variable in KDB+?

A) var := value
B) var : value
C) CREATE SCALAR var AS value
D) None of the above

Answer: A) var := value

Explanation: To create a scalar variable in KDB+, the := operator is used to assign a value to a variable.