pkg database/sql, method (*DB) QueryRow(string, ...interface{}) *Row
pkg database/sql, method (*NullBool) Scan(interface{}) error
pkg database/sql, method (*NullFloat64) Scan(interface{}) error
pkg database/sql, method (*NullInt64) Scan(interface{}) error
pkg database/sql, method (*NullString) Scan(interface{}) error
pkg database/sql, method (*Row) Scan(...interface{}) error
pkg database/sql, method (*Rows) Close() error

pkg crypto/x509, const PureEd25519 SignatureAlgorithm
pkg database/sql, method (*Conn) Raw(func(interface{}) error) error
pkg database/sql, method (*NullInt32) Scan(interface{}) error
pkg database/sql, method (NullInt32) Value() (driver.Value, error)
pkg database/sql, method (*NullTime) Scan(interface{}) error
pkg database/sql, method (NullTime) Value() (driver.Value, error)
pkg database/sql, type NullInt32 struct

uint(m.BitLen()) logR := _W * n // We start by computing R = 2^(_W * n) mod m. We can get pretty close, to // 2^⌊log₂m⌋, by setting the highest bit we can without having to reduce. rr.limbs[n-1] = 1 << ((mLen - 1) % _W) // Then we double until we reach 2^(_W * n). for i := mLen - 1; i < logR; i++ { rr.Add(rr, m) } // Next we need to get from R to 2^(_W * n) R mod m (aka from one to R in // the Montgomery domain, meaning we can use Montgomery multiplication now). // We could do that by doubling _W * n times,...

uint(m.BitLen()) logR := _W * n // We start by computing R = 2^(_W * n) mod m. We can get pretty close, to // 2^⌊log₂m⌋, by setting the highest bit we can without having to reduce. rr.limbs[n-1] = 1 << ((mLen - 1) % _W) // Then we double until we reach 2^(_W * n). for i := mLen - 1; i < logR; i++ { rr.Add(rr, m) } // Next we need to get from R to 2^(_W * n) R mod m (aka from one to R in // the Montgomery domain, meaning we can use Montgomery multiplication now). // We could do that by doubling _W * n times,...

{* ../../docs_src/query_params_str_validations/tutorial006_an_py39.py hl[9] *}

### Required, can be `None` { #required-can-be-none }

You can declare that a parameter can accept `None`, but that it's still required. This would force clients to send a value, even if the value is `None`.

There are several parameters that you can pass to your *path operation decorator* to configure it.

/// warning

Notice that these parameters are passed directly to the *path operation decorator*, not to your *path operation function*.

///

## Response Status Code { #response-status-code }

You can define the (HTTP) `status_code` to be used in the response of your *path operation*.

You can pass directly the `int` code, like `404`.

# Response Model - Return Type { #response-model-return-type }

You can declare the type used for the response by annotating the *path operation function* **return type**.

You can use **type annotations** the same way you would for input data in function **parameters**, you can use Pydantic models, lists, dictionaries, scalar values like integers, booleans, etc.

{* ../../docs_src/response_model/tutorial001_01_py310.py hl[16,21] *}

# Path Parameters and Numeric Validations { #path-parameters-and-numeric-validations }

In the same way that you can declare more validations and metadata for query parameters with `Query`, you can declare the same type of validations and metadata for path parameters with `Path`.

## Import `Path` { #import-path }

First, import `Path` from `fastapi`, and import `Annotated`:

{* ../../docs_src/path_params_numeric_validations/tutorial001_an_py310.py hl[1,3] *}

You can probably skip this part.

///

There's an alternative way to define this logic to be executed during *startup* and during *shutdown*.

You can define event handlers (functions) that need to be executed before the application starts up, or when the application is shutting down.

These functions can be declared with `async def` or normal `def`.

///

This is of course not the frontend for the final users, but it's a great automatic tool to document interactively all your API.

It can be used by the frontend team (that can also be yourself).

It can be used by third party applications and systems.

And it can also be used by yourself, to debug, check and test the same application.

## The `password` flow { #the-password-flow }