Trait FromValue 

pub trait FromValue: Sized {
    // Required method
    fn from_value(value: &Value) -> Result<Self>;
}

A Rust type a column can be read into.

The conversions are deliberately forgiving in one direction only: an Int column reads into f64, but text never silently parses into a number, so a schema mistake surfaces as an error instead of a wrong value.

Required Methods

fn from_value(value: &Value) -> Result<Self>

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl FromValue for String

fn from_value(value: &Value) -> Result<Self>

impl FromValue for Vec<u8>

fn from_value(value: &Value) -> Result<Self>

impl FromValue for bool

fn from_value(value: &Value) -> Result<Self>

impl FromValue for f64

fn from_value(value: &Value) -> Result<Self>

impl FromValue for i32

fn from_value(value: &Value) -> Result<Self>

impl FromValue for i64

fn from_value(value: &Value) -> Result<Self>

impl<T: FromValue> FromValue for Option<T>

A nullable column reads into Option<T>; every other type treats NULL as an error, which is what makes a missing value impossible to ignore by accident.

fn from_value(value: &Value) -> Result<Self>

Implementors

impl FromValue for Json

impl FromValue for Value