Database query optimization in Flask - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to fetch all users from the database using Flask-SQLAlchemy.

Flask

users = User.query.[1]()

Drag options to blanks, or click blank then click option'

Afirst

Bfilter

Cget

Dall

Attempts:

3 left

💡 Hint

Common Mistakes

Using filter() without conditions causes an error.

Using get() requires a primary key argument.

The all() method fetches all records from the query.

2fill in blank

medium

Complete the code to filter users with age greater than 30.

Flask

users = User.query.filter(User.age [1] 30).all()

Drag options to blanks, or click blank then click option'

A>

B<

C==

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using == filters only users exactly 30 years old.

Using <= includes users 30 or younger.

The > operator filters users older than 30.

3fill in blank

hard

Fix the error in the query to get the first user with name 'Alice'.

Flask

user = User.query.filter_by(name=[1]).first()

Drag options to blanks, or click blank then click option'

A"Alice"

BAlice

C'Alice'

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Not quoting the string causes a NameError.

Using variable name instead of string literal.

String values must be quoted in Python queries. Use single or double quotes.

4fill in blank

hard

Fill both blanks to optimize the query by selecting only 'id' and 'name' columns.

Flask

users = db.session.query(User.[1], User.[2]).all()

Drag options to blanks, or click blank then click option'

Aid

Bage

Cname

Demail

Attempts:

3 left

💡 Hint

Common Mistakes

Selecting all columns when only a few are needed.

Choosing wrong columns that are not required.

Selecting only needed columns reduces data load and speeds up queries.

5fill in blank

hard

Fill all three blanks to create a query that orders users by age descending and limits to 5 results.

Flask

users = User.query.order_by(User.[1].[2]()).[3](5).all()

Drag options to blanks, or click blank then click option'

Aage

Bdesc

Climit

Dasc

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'asc' instead of 'desc' for descending order.

Forgetting to limit the number of results.

Ordering by age descending uses desc(), and limit(5) restricts results to 5.