Trait tokio_postgres_extractor::RowExtractExt

pub trait RowExtractExt: Sealed {
    // Required methods
    fn extract_once<'row, T>(&'row self) -> T
       where T: Extract<'row>;
    fn extract<'row, T>(
        &'row self,
        columns: &mut Option<<T as Columns>::Columns>
    ) -> T
       where T: Extract<'row>;
    fn extract_with_columns<'row, T>(
        &'row self,
        columns: &<T as Columns>::Columns
    ) -> T
       where T: Extract<'row>;
}

Extension trait for extracting from a Row.

Required Methods

fn extract_once<'row, T>(&'row self) -> Twhere T: Extract<'row>,

Extracts an instance of T from this Row.

This is equivalent to T::extract_once(self).

Panics

Panics if Extract::extract_once panics.

Examples

#[derive(Columns, Extract)]
struct User<'a> {
    id: i32,
    name: &'a str,
}

fn map_user(row: &Row) -> User<'_> {
    row.extract_once()
}

fn extract<'row, T>( &'row self, columns: &mut Option<<T as Columns>::Columns> ) -> Twhere T: Extract<'row>,

Extracts an instance of T from this Row, memorizing the mapping between fields and columns.

This is equivalent to T::extract(columns, self).

Panics

Panics if Extract::extract panics.

Examples

#[derive(Columns, Extract)]
struct User<'a> {
    id: i32,
    name: &'a str,
}

fn map_users(rows: &[Row]) -> Vec<User<'_>> {
    let mut columns = None;
    rows.iter().map(|row| row.extract(&mut columns)).collect()
}

fn extract_with_columns<'row, T>( &'row self, columns: &<T as Columns>::Columns ) -> Twhere T: Extract<'row>,

Extracts an instance of T from this Row and a mapping between the fields and columns.

This is equivalent to T::extract_with_columns(columns, self).

Panics

Panics if Extract::extract_with_columns panics.

Implementations on Foreign Types

impl RowExtractExt for Row

fn extract_once<'row, T: Extract<'row>>(&'row self) -> T

fn extract<'row, T>( &'row self, columns: &mut Option<<T as Columns>::Columns> ) -> Twhere T: Extract<'row>,

fn extract_with_columns<'row, T>( &'row self, columns: &<T as Columns>::Columns ) -> Twhere T: Extract<'row>,

Implementors