sql for data science with r coursera answers week 6

Final Exam

Final Exam

1. Which of the following displays correct syntax for the SELECT statement that retrieves data from the “MovieName” column in a table named “Movie?”

  • SELECT MovieName FROM Movie;
  • SELECT MovieName, Movie;
  • SELECT Movie FROM MovieName;
  • FROM Movie SELECT MovieName;

2. What is wrong with the following INSERT statement?

INSERT INTO Movie (MOVIE_ID, MOVIE TITLE, RELEASE_YEAR) VALUES (52, ‘Princess Bride’, 1987), (‘When Harry Met Sally’, 1989);

  • It is missing the keyword “COLUMNS.”
  • The column names are in the incorrect order.
  • The word “INTO” should be removed.
  • It is missing a value.

 

3. Which of the following would be attributes in an entity-relationship (ER) diagram for an entity named “Dog?”

  • German Shepherd, Fido, green, short-haired, female
  • German Shepherd, Malamute, Chihuahua, Labrador, Golden Retriever
  • breed, fur type name, eye color, gender
  • breed, German Shepherd, Fido, name, eye color

4. Which two statements are true regarding data manipulation language (DML) operations?

  • They are used to define, change, or drop database objects such as tables.
  • They are often referred to as create, read, updates, and delete (CRUD) operations.

  • They are used to read and modify data in tables.

  • They are used to define relationships among tables.

 

5. Which of the following SQL statements is equivalent to “SELECT title, pages FROM Book WHERE pages >= 290 AND pages <= 300;”?

  • SELECT title, pages FROM Book WHERE pages BETWEEN 290 AND 300;
  • SELECT pages BETWEEN 290 AND 300 FROM Book;
  • SELECT title, pages FROM Book WITH pages BETWEEN 290 AND 300;
  • None of the above. There is not another equivalent form of that SQL statement.

6. Which would be the result of the SQL statement

SELECT TeamName, COUNT(*) FROM Roster GROUP BY TeamName;

  • Return a list of all players on each team
  • Counts the total number of players on a team listed in the “Roster” table and displays the results by “TeamName”.
  • Counts the total number of players on all teams listed in the “Roster” table
  • Lists a specific count associated with each team.

 

7. Which statement describes a schema?

  • It is a collection of observations.
  • It is similar in structure to an R dataframe.
  • It groups a set of tables together in a database.
  • It is a subset of a table’s attributes.

8. How should dates and times be mapped from R to a relational database management system (RDBMS)?

  • As integers
  • As strings
  • Using the toDate() method
  • As objects

 

9. Which RODBC method is most closely associated with the SQL TRUNCATE statement?

  • sqlRemove()
  • sqlDrop()
  • sqlClear()
  • sqlTrim()

10. What is the purpose of the sqlFetch() function?

  • To select all the data in a table
  • To get data from the RDBMS and create a histogram in R
  • To get data from the R object database management system (RODBMS) and create a box plot in R
  • Converts character data into vector data

11. Which statement is the correct way to retrieve the player who scored the most points per game on each basketball team?

  • SELECT TeamName, PlayerName, MAX(GamePoints) FROM Scores;
  • SELECT TeamName, PlayerName FROM Scores WHERE MAX(GamePoints);
  • SELECT TeamName, GamePoints, MAX(PlayerName) FROM Scores;
  • SELECT TeamName, PlayerName, MAX FROM Scores;

12. Which of the following is the correct general syntax for the INSERT statement?

  • INSERT <column name> INTO <table name>;
  • INSERT <table name> INTO <column name> VALUES {[value], [value],…};
  • INSERT INTO <table name> (column1, column2…) VALUES (value1, value2…);
  • INSERT INTO <table name> WHERE <column name> EQUALS <primary key> WITH VALUES

13. What data would be returned from this SQL statement?

SELECT firstname FROM Book WHERE firstname LIKE R%;

  • Returns data from the column named “firstname” from the “Book” table if the first letter of “firstname” is ‘R’
  • Returns data from the column named “firstname” from the “Book” table if the “firstname” contains an R
  • Returns data from the column named “firstname” from the “Book” table if the first letter of “firstname” is NOT ‘R’
  • Returns data in the row whose primary key is “firstname” from the “Book” table if the first letter of the Book name is ‘R’

14. What feature in a relational database management system is similar to an observation in R?

  • A row
  • An attribute
  • A table
  • A primary key

15. Data that needs transformed into a factor is generally transferred from an R object database management system (RODBMS) into R as what data type?

  • A float
  • An object
  • A Boolean
  • A character

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