Aggregate Functions and Transactions

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1 of 12

Question1
Which statement best describes “Aggregate Functions” in MySQL?
- It's a single function that is a collection of multiple functions running in a sequence
- It's a function that operates on multiple values and returns one value as a result.
- It's a function defined by the developer that has another function nested within it
- It's a function that runs automatically when a certain action happens within the database
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2 of 12

Question2
Which of the following statements is incorrect regarding the MySQL code below?
- It will count how many unique values of runner_id there are in the table and provide the result
- It will group all the rows for each runner_id together and operate the function on each group
- The final result table that will be displayed will be sorted by the runner_id
- All of the rows within the table will be considered in this operation as a default unless defined otherwise
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3 of 12

Question3
What is the correct aggregate function in MySQL to calculate the average of multiple fields?
- AVERAGE(field_name)
- AVE(field_name)
- AVR(field_name)
- AVG(field_name)
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4 of 12

Question4
For a database on the ER Diagram below, the following MySQL code has been written. Which of the following statements is incorrect in regards of the MySQL code?
- This will only consider race records that have a matching course_id in the course table
- It will show the best (shortest/lowest time) race results for each course
- It will show the overall average race result over all the courses combined
- The final output will be sorted by the course_id
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5 of 12

Question5
For a database built in MySQL based on the ER Diagram below, which of the following code examples will provide the longest race result for each runner?
- SELECT runner_id, MAX(race_result) GROUP BY runner_id;
- SELECT runner_id, MAX(race_result) FROM race GROUP BY runner_id;
- SELECT runner_id, MAX(race_result) INNER JOIN race AND runner GROUP BY runner_id;
- SELECT runner_id, MAX(race_result) FROM race FOR EACH runner_id;
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6 of 12

Question6
In MySQL, what is the meaning of the COMMIT command?
- It will conclude the transaction and make the changes made during the transaction accessible
- It will indicate the beginning of a transaction within the code
- It will make any changes made so far permanent, unless the table is dropped and re-created
- It will make any changes made only available to the current user and not others
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7 of 12

Question7
Which of the following is most correct regarding transactions in MySQL?
- It provides an important feature in lowering the amount of storage the database uses, especially when there are multiple users
- It provides a method to run various complex actions much faster than databases that do not have this feature
- It provides means to fully automate certain actions that will execute when pre-defined situations occur
- It provides methods to keep the data consistent throughout the database through multiple users and complex actions
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8 of 12

Question8
Which of the following situations would using a TRANSACTION/COMMIT/ROLLBACK provide a direct solution?
- When you have to execute two actions in sequence and don't want the first to make changes unless both actions are successful
- When you have to make changes to the database that are only accessible to certain users and not others
- When you have to make a large amount of changes that you are afraid will take too much time, and want them to execute quicker
- When you want more flexibility in the database to make changes without being limited in actions due to primary and foreign key connections
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9 of 12

Question9
In the case of getting the error code below, which of the following is not a viable path forward?

Error Code: 1451. Cannot delete or update a parent row: a foreign key constraint fails…
- Change the foreign key check parameters to force the delete and switch it back to default afterwards
- Delete the records in the child table with the foreign keys first, then delete the records in the parent table with the primary keys
- Alter the properties of the tables so that there is a cascading deletion action in these cases
- Nest the same code within a transaction and commit the changes when it's done
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10 of 12

Question10
Which of the following is incorrect in regards of the MySQL code below?
- It temporarily redefined the delimiter to "//" so it could nest SQL code using ";" as the delimiter
- This is a blank example of how a procedure is defined in MySQL
- This procedure is set to work with a table named "runner_to_delete"
- This procedure could be executed by using the CALL command
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Question
11 of 12

Question11
Which of the following is incorrect regarding the MySQL code below?
- @runner_id_to_delete is being used as a variable
- If @runner_id_to_delete has no value, then any actions taken so far in this transaction will be reversed
- Regardless of the database set-up, the order of tables to delete records from does not matter
- A variable is being utilized so that this code could be part of a procedure that takes in different values as a parameter
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12 of 12

Question12
Which of the following is not a benefit developers intend to leverage by using procedures in MySQL?
- Procedures become re-usable code, so developers don't have to constantly re-write code for situations that occur frequently
- Procedures could be controlled centrally, so changes to a procedure will immediately come into effect for all the cases that the procedure is being used
- Procedures provide a way to keep specific code hidden from users and makes the specific actions more simple to implement
- Procedures offer flexibility as the same procedure could be altered during execution by different users
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