Why query parameters filter data in FastAPI - Quick Recap

Recall & Review

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What are query parameters in FastAPI?

Query parameters are parts of the URL that come after a question mark (?) and are used to send extra information to the server. They help specify what data the client wants.

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How do query parameters help filter data in FastAPI?

They let users tell the server exactly what data to return by adding conditions in the URL, like filtering a list to show only items that match those conditions.

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Example: How to define an optional query parameter in FastAPI?

Use function parameters with default values. For example, def read_items(q: str = None): means the query parameter 'q' is optional.

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Why is filtering data with query parameters better than sending all data?

Filtering reduces the amount of data sent over the network, making responses faster and easier to handle, just like choosing only the fruits you want from a basket.

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What happens if you don't use query parameters to filter data?

The server sends all data, which can be slow and overwhelming. Query parameters help avoid this by letting you ask for just what you need.

What symbol starts query parameters in a URL?

A &

B #

C /

D ?

Query parameters always start after a question mark (?) in a URL.

In FastAPI, how do you make a query parameter optional?

A Set a default value in the function parameter

B Use a special decorator

C Make the parameter a global variable

D Use a POST request instead

Setting a default value like None makes the query parameter optional.

Why use query parameters to filter data?

A To make the URL shorter

B To get only the data you want

C To change the server code

D To send data to the client

Query parameters help you ask for specific data, filtering results.

Which of these is a valid query parameter example?

A /items/color/red/size/large

B /items#color=red

C /items?color=red&size=large

D /items/color=red&size=large

Query parameters come after ? and are separated by &.

What happens if you omit query parameters when calling a FastAPI endpoint?

A The endpoint uses default values or returns all data

B The server crashes

C The client gets an error message

D The URL changes automatically

If query parameters are optional, the endpoint uses defaults or returns unfiltered data.

Explain in your own words why query parameters are useful for filtering data in FastAPI.

Think about how you ask for specific items in a store.

Describe how to define and use an optional query parameter in a FastAPI function.

Look at function parameters with = None.