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21.15. Multiple Choice Questions

Q-1: Looking at the code below, what would this line do?

INSERT INTO Cats (name, breed) VALUES ('Petunia', 'American Shorthair')

• Add a table to the Cats database with the name "Petunia" and breed "American Shorthair".
• Try Again! Inserts adds a row to a table.
• Add a row to the Cats table with the name "Petunia" and the breed "American Shorthair".
• Correct! This will insert a row in the table Cats with the name "Petunia" and the breed "American Shorthair".
• Create the table Cats.
• Try Again! This line wouldn't create a new table.
• Add a row to the Cats table with the name "American Shorthair" and the breed "Petunia".
• Try Again! Check the order of the columns and values.

Q-2: Looking at the code below, what would this line do to the table Cats?

cur.execute('DROP TABLE IF EXISTS Cats ')

• It will remove the row "Cats".
• Try again! "Cats" is not a tuple (row).
• It will move "Cats" to the end of the database.
• Try again! That's not quite what drop means in SQL.
• It will remove the column "Cats".
• Try again! "Cats" is not an attribute (column).
• It will remove the table "Cats".
• Correct! "Cats" is a relation (table), so this line will remove it from the database.

Q-3: Which SQL keyword is used to combine rows from two tables in a database?

• IN
• Try again! The IN operator allows you to specify multiple values in a WHERE clause
• JOIN
• Correct! A JOIN clause is used to combine rows from two or more tables, based on a related column between them.
• BETWEEN
• Try again! The BETWEEN operator selects values within a given range.
• SELECT INTO
• Try again! The SELECT INTO statement copies data from one table into a new table.

Q-4: How can you delete all of the rows where the “name” is “Ruby” in the Cats Table?

• DELETE FROM Cats WHERE name = 'Ruby'
• Correct! This tells the program to remove all rows with a name equal to "Ruby" from the "Cats" table.
• DELETE name='Ruby' FROM Cats
• Try again! The table should be called first.
• DELETE ROW name='Ruby' FROM Cats
• Try again! You do not need to use the command "ROW". It will already delete the data associated with Ruby's entry.
• DELETE FROM Cats WHERE name == 'Ruby'
• Try again! You do not use == in SQL

Q-5: Which of the following is not a SQL constraint?

• UNIQUE
• Try again! This constraint ensures that all values in a column are different
• PRIMARY KEY
• Try again! This constraint uniquely identifies each row in a table.
• LOGICAL KEY
• Correct! This is not a SQL constraint, because it is what *we* use to refer to a row, not the program's identifier.
• NOT NULL
• Try again! This constraint ensures that a column cannot have a NULL value.

Q-6: Which command will try to remove data from a table in a database?

• DELETE
• Correct! Delete will try to remove data from a database.
• REMOVE
• Try Again! Remove is not a valid keyword for database.
• COLLAPSE
• Try Again! Collapse is not a valid keyword for a database.
• DROP
• Try Again! This is used to delete an entire table from a database.

Q-7: Which is the correct command for a statement that will select data from the Breed column in the Cats table?

• SELECT FROM Breed,Cats
• Try again! The order of the commands and names are mixed up and no commas are necessary here!
• SELECT Cats FROM Breed
• Try again! The SELECT command should be followed by column name and the ROW command should be followed by a table name.
• SELECT Breed FROM Cats
• Correct! This command is very straight forward! It selects the breed from the table cats
• FROM Cats SELECT Breed
• Try again! The commands are in the wrong order. The SELECT command should come before the FROM command.

Q-8: True or False? The following line will select all columns for the name “Bernard” from the table “Cats”.

SELECT * FROM Cats WHERE name = 'Bernard'

• True
• Correct! * indicates that you want the database to return all of the columns for each row that matches the WHERE clause.
• False
• Try again! What does the * indicate?

Q-9: True or False? SQLite will not let two programs change the same data at the same time.

• True
• Correct! SQLite takes care to keep two programs from changing the same data at the same time, so make sure you save frequently!
• False
• Try again! You cannot change the same data at the same time on SQLite.

Q-10: True or False? A cursor is used to create a database.

• True
• Try again! A connection is used to create a database, while a cursor is used to execute SQL commands on the database.
• False
• Correct! A cursor is used to execute SQL commands in a database and retrieve data from the database, not create one.

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