Trait mz_repr::fixed_length::FromRowByTypes

pub trait FromRowByTypes: Sized + Default {
    // Required methods
    fn from_datum_iter<'a, I, D>(
        &mut self,
        datum_iter: I,
        types: Option<&[ColumnType]>
    ) -> Self
       where I: IntoIterator<Item = D>,
             D: Borrow<Datum<'a>>;
    fn try_from_datum_iter<'a, I, D, E>(
        &mut self,
        datum_iter: I,
        types: Option<&[ColumnType]>
    ) -> Result<Self, E>
       where I: IntoIterator<Item = Result<D, E>>,
             D: Borrow<Datum<'a>>;

    // Provided method
    fn from_row(&mut self, row: Row, types: Option<&[ColumnType]>) -> Self { ... }
}

A helper trait to construct target values from input Row instances based on type information that only manifests at runtime (typically originating from inferred schemas). Typically, the target type will be of fixed-length without tags per column or Row itself.

Required Methods

fn from_datum_iter<'a, I, D>( &mut self, datum_iter: I, types: Option<&[ColumnType]> ) -> Self

where I: IntoIterator<Item = D>, D: Borrow<Datum<'a>>,

Obtains an instance of Self' given an iterator of borrowed datums and a schema provided by types`.

Implementations are free to place specific requirements on the given schema.

fn try_from_datum_iter<'a, I, D, E>( &mut self, datum_iter: I, types: Option<&[ColumnType]> ) -> Result<Self, E>

where I: IntoIterator<Item = Result<D, E>>, D: Borrow<Datum<'a>>,

Obtains an instance of Self' given an iterator of results of borrowed datums and a schema provided by types`.

Implementations are free to place specific requirements on the given schema.

In the case the iterator produces an error, the pushing of datums is terminated and the error returned.

Provided Methods

fn from_row(&mut self, row: Row, types: Option<&[ColumnType]>) -> Self

Obtains an instance of Self given an instance of Row and a schema provided by types.

Implementations are free to place specific requirements on the given schema.

Object Safety

This trait is not object safe.

Implementations on Foreign Types

impl FromRowByTypes for ()

fn from_row(&mut self, row: Row, types: Option<&[ColumnType]>) -> Self

Obtains a unit value from an empty Row.

This implementation panics if types other than Some(&[]) are provided. This is because unit values need to have an empty schema.

fn from_datum_iter<'a, I, D>( &mut self, datum_iter: I, types: Option<&[ColumnType]> ) -> Self

where I: IntoIterator<Item = D>, D: Borrow<Datum<'a>>,

Obtains a unit value from an empty datum iterator.

This implementation panics if types other than Some(&[]) are provided. This is because unit values need to have an empty schema.

fn try_from_datum_iter<'a, I, D, E>( &mut self, datum_iter: I, types: Option<&[ColumnType]> ) -> Result<Self, E>

where I: IntoIterator<Item = Result<D, E>>, D: Borrow<Datum<'a>>,

Obtains a unit value from an empty iterator of results of datums.

This implementation panics if types other than Some(&[]) are provided. This is because unit values need to have an empty schema.

Implementors

impl FromRowByTypes for Row