[−][src]Trait mysql::prelude::FromValue

pub trait FromValue {
    type Intermediate: ConvIr<Self>;
    fn from_value(v: Value) -> Self { ... }
    fn from_value_opt(v: Value) -> Result<Self, FromValueError> { ... }
    fn get_intermediate(v: Value) -> Result<Self::Intermediate, FromValueError> { ... }
}

Implement this trait to convert value to something.

FromRow requires ability to cheaply rollback FromValue conversion. This ability is provided via Intermediate associated type.

Example implementation:

#[derive(Debug)]
pub struct StringIr {
    bytes: Vec<u8>,
}

impl ConvIr<String> for StringIr {
    fn new(v: Value) -> MyResult<StringIr> {
        match v {
            Value::Bytes(bytes) => match from_utf8(&*bytes) {
                Ok(_) => Ok(StringIr { bytes: bytes }),
                Err(_) => Err(Error::FromValueError(Value::Bytes(bytes))),
            },
            v => Err(Error::FromValueError(v)),
        }
    }
    fn commit(self) -> String {
        unsafe { String::from_utf8_unchecked(self.bytes) }
    }
    fn rollback(self) -> Value {
        Value::Bytes(self.bytes)
    }
}

impl FromValue for String {
    type Intermediate = StringIr;
}

Associated Types

`type Intermediate: ConvIr<Self>`

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Provided methods

`fn from_value(v: Value) -> Self`

Will panic if could not convert v to Self.

`fn from_value_opt(v: Value) -> Result<Self, FromValueError>`

Will return Err(Error::FromValueError(v)) if could not convert v to Self.

`fn get_intermediate(v: Value) -> Result<Self::Intermediate, FromValueError>`

Will return Err(Error::FromValueError(v)) if v is not convertible to Self.

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Implementations on Foreign Types

`impl FromValue for u64`[src]

`type Intermediate = ParseIr<u64>`

`impl FromValue for u128`[src]

`type Intermediate = ParseIr<u128>`

`impl FromValue for Decimal`[src]

`type Intermediate = ParseIr<Decimal>`

`fn from_value(v: Value) -> Decimal`[src]

`impl FromValue for NaiveTime`[src]

`type Intermediate = ParseIr<NaiveTime>`

`impl FromValue for i8`[src]

`type Intermediate = ParseIr<i8>`

`impl FromValue for Duration`[src]

`type Intermediate = ParseIr<Duration>`

`impl FromValue for u16`[src]

`type Intermediate = ParseIr<u16>`

`impl FromValue for Duration`[src]

`type Intermediate = ParseIr<Duration>`

`impl FromValue for u32`[src]

`type Intermediate = ParseIr<u32>`

`impl FromValue for BigUint`[src]

`type Intermediate = ParseIr<BigUint>`

`fn from_value(v: Value) -> BigUint`[src]

`impl FromValue for Date`[src]

`type Intermediate = ParseIr<Date>`

`impl<T> FromValue for Option<T> where T: FromValue,` [src]

`type Intermediate = OptionIr<<T as FromValue>::Intermediate>`

`impl FromValue for u8`[src]

`type Intermediate = ParseIr<u8>`

`impl FromValue for Vec<u8>`[src]

`type Intermediate = Vec<u8>`

`impl FromValue for BigDecimal`[src]

`type Intermediate = ParseIr<BigDecimal>`

`fn from_value(v: Value) -> BigDecimal`[src]

`impl FromValue for Time`[src]

`type Intermediate = ParseIr<Time>`

`impl FromValue for String`[src]

`type Intermediate = Vec<u8>`

`impl FromValue for f32`[src]

`type Intermediate = ParseIr<f32>`

`impl FromValue for Uuid`[src]

`type Intermediate = UuidIr`

`impl FromValue for Duration`[src]

`type Intermediate = ParseIr<Duration>`

`impl FromValue for bool`[src]

`type Intermediate = ParseIr<bool>`

`impl FromValue for BigInt`[src]

`type Intermediate = ParseIr<BigInt>`

`fn from_value(v: Value) -> BigInt`[src]

`impl FromValue for i32`[src]

`type Intermediate = ParseIr<i32>`

`impl FromValue for NaiveDate`[src]

`type Intermediate = ParseIr<NaiveDate>`

`impl FromValue for i64`[src]

`type Intermediate = ParseIr<i64>`

`impl FromValue for i16`[src]

`type Intermediate = ParseIr<i16>`

`impl FromValue for i128`[src]

`type Intermediate = ParseIr<i128>`

`impl FromValue for PrimitiveDateTime`[src]

`type Intermediate = ParseIr<PrimitiveDateTime>`

`impl FromValue for usize`[src]

`type Intermediate = ParseIr<usize>`

`impl FromValue for isize`[src]

`type Intermediate = ParseIr<isize>`

`impl FromValue for NaiveDateTime`[src]

`type Intermediate = ParseIr<NaiveDateTime>`

`impl FromValue for f64`[src]

`type Intermediate = ParseIr<f64>`

`impl FromValue for Value`[src]

`type Intermediate = JsonIr`

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Implementors

`impl FromValue for mysql::Value`[src]

`type Intermediate = Value`

`fn from_value(v: Value) -> Value`[src]

`fn from_value_opt(v: Value) -> Result<Value, FromValueError>`[src]

`impl<T> FromValue for Deserialized<T> where T: DeserializeOwned,` [src]

`type Intermediate = DeserializedIr<T>`

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