CRUD operations in Flask - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does CRUD stand for in web development?

CRUD stands for Create, Read, Update, and Delete. These are the four basic operations to manage data in an application.

beginner

In Flask, which HTTP methods are commonly used for each CRUD operation?

Create: POST<br>Read: GET<br>Update: PUT or PATCH<br>Delete: DELETE

beginner

How do you define a route in Flask to handle a GET request for reading data?

Use the @app.route decorator with methods=['GET']. For example:<br>

@app.route('/items', methods=['GET'])<br>def get_items():<br>    return 'List of items'

intermediate

What is the purpose of the Flask request object in CRUD operations?

The request object holds data sent by the client, such as form data or JSON payloads. It helps to access input when creating or updating data.

intermediate

Why is it important to handle errors in CRUD operations in Flask?

Handling errors ensures the app responds clearly when something goes wrong, like missing data or invalid input. It improves user experience and app stability.

Which HTTP method is typically used to update existing data in a Flask app?

A POST

B GET

C PUT

D DELETE

PUT is commonly used to update existing data, while POST is for creating new data.

What Flask decorator is used to define a route for a CRUD operation?

A @app.route

B @app.method

C @app.handle

D @app.request

The @app.route decorator defines URL routes and HTTP methods in Flask.

Which CRUD operation corresponds to the HTTP DELETE method?

A Create

B Read

C Update

D Delete

DELETE is used to remove data from the server.

In Flask, how do you access JSON data sent in a POST request?

A request.json

B request.form

C request.args

D request.data

request.json provides parsed JSON data sent by the client.

Why should you specify HTTP methods in Flask routes for CRUD?

A To improve app speed

B To restrict route to intended operations

C To allow all methods by default

D To enable database connections

Specifying methods restricts routes to handle only intended CRUD operations, improving security and clarity.

Explain how you would implement the four CRUD operations in a Flask app, including which HTTP methods and Flask features you would use.

Think about how URLs and HTTP methods map to CRUD actions.

Describe why error handling is important in CRUD operations in Flask and how you might handle a missing resource when trying to update or delete.

Consider what happens if the user tries to change data that does not exist.