Database Challenges

After completing the code-along, attempt the challenges below. These exercises will reinforce the database skills from the code-along.

After working on the challenges for a while, feel free to start working on the final project.

Challenge 1: Adding a 'Date of Visit' Property to Review Objects

In this challenge, add a new piece of data to store with each Restaurant Review object: the date that the reviewer visited the restaurant. For the purposes of this exercise, the date will be stored as a simple string.

Part A: Updating the add_review Function

First, update the add_review function so that it can handle the new "date of visit" value.

1. Open the reviews.py file for editing
2. Find the add_review function
3. Add a parameter to the function: date_of_visit
4. Find the new dictionary that is added to the database with db[new_db_key]
5. Add a new key to the dictionary: 'date_of_visit'
6. Set the value for the 'date_of_visit' key to be the date_of_visit parameter

Run the program, and try adding a new review. At this point, it should fail - the call to the add_review function does not have the proper arguments!

Part B: Updating the prompt_for_add_review Function

Now that the add_review function can handle the new property, make sure the user is asked for it as well.

1. Open the main.py file for editing
2. Find the prompt_for_add_review function
3. Under the text variable, create a new variable named date_of_visit
4. Set the date_of_visit variable to an input asking what date the user visited the restaurant
5. Pass the date_of_visit variable into the add_review function call

Run the program again, and now try adding a new review. It should work! The date_of_visit value should be stored in the database. But it is currently not possible to see the information anywhere.

Part C: Updating the print_reviews Function

Next, make sure the user can actually see each review date when they view all reviews.

1. Open the main.py file for editing
2. Find the print_reviews function
3. Find the for loop that loops through review_list
4. Make a new line under the line that prints out the score for the review
5. On that line, print out the date of visit for the review, e.g.: Date of Visit: Oct 10, 2010

Run the program once more, print all reviews, and verify that it is possible to see the date of visit for each new review!

Challenge 2: Adding a Command to Print Certain Restaurant Reviews

In this challenge, add a command to the application that allows the user to select a certain restaurant, and see reviews only for that restaurant. Note that there are several different ways to accomplish this, so feel free to do whatever works.

Part A: Defining the Function

First, define a new function that will execute the command.

1. Open the main.py file for editing
2. Under the print_reviews function definition, define a new function named print_reviews_for_restaurant
3. In the body of the print_reviews_for_restaurant function, add os.system('clear') to clear the console
4. Next, create a variable named restaurant_filter
5. Set restaurant_filter to an input asking which restaurant to find reviews for
6. Under that, get the reviews by using reviews.get_reviews()
   • Store the result in a variable named reviews
7. Under that, create a for loop that loops through each review in reviews
8. In the body of the for loop, check if the 'restaurant' for the review matches restaurant_filter
   • If it does, print out the review
   • If it does not, do nothing

Now the function is defined, but it will not do anything until it is called.

Part B: Adding the Command

Next, add a command in the while True loop to handle printing reviews for a certain restaurant.

1. At the bottom of the menu, print out [1] View Reviews for Restaurant
2. Create an elif that checks if the user entered 1
3. If they did, call the print_reviews_for_restaurant function

Run the program, and verify that it is possible to see all reviews for only one restaurant!

(BONUS) Part C: Refactoring

Try to figure out a different way to create this functionality. Currently, some code is being repeated that prints out each restaurant. See if it is possible to make this work better.

Challenge 3: Handling Improper Scores

Currently, it is possible to enter any score for a review. It should only be possible to enter a number between 0 and 10. Fix the code to prevent the user from entering a score outside of those boundaries.

1. Open the main.py file for editing
2. Find the prompt_for_add_review function
3. Find where the score variable is set in the function
4. Under that, create an if statement checking if score is outside the range of 0 and 10
5. If it is, print a message saying "ERROR" and return
6. Make a similar change to the prompt_for_update_review function

Run the program, and verify that it is impossible to enter a score that is greater than 10, or less than 0.

(BONUS) No Non-numeric Input

Currently, if the user enters something other than a number for the score, the program crashes. Fix it so that the error is handled more gracefully. This may require some research.

(BONUS) Challenge 4: Sorting the Reviews

In the current version of the app, the reviews are not printed in any particular order. Figure out how to sort them in a couple different ways:

• Alphabetically by restaurant name
• Chronologically by date of visit
• Ranked by score

The program should ask the user how to sort the reviews before printing them.

(BONUS) Challenge 5: Adding Authentication

At this point, any person who enters the application will be able to add a review. Fix it so that a user must be logged in to add reviews. There are several ways to do this, but here is some guidance:

• Add a user property to each object in the database
• Store a list of users in the database
• Allow users to create an account
• Only allow users to edit their own reviews
• Create a log-in mechanism where users enter their name and a password
• Allow a user to see their own reviews

Feel free to learn more about authentication before diving into this challenge.

Beyond

There are infinite possibilities with the Replit DB. Try to build a completely new application, possibly a Flask web app, a Pygame game, or a Discord bot, that uses a database. This can also lead directly into the final project.