Trait postgres_query::extract::FromSqlRow

pub trait FromSqlRow: Sized {
    const COLUMN_COUNT: usize;

    fn from_row<R>(row: &R) -> Result<Self, Error>
    where
        R: Row;

    fn from_row_multi<R>(rows: &[R]) -> Result<Vec<Self>, Error>
    where
        R: Row,
    { ... }
}

Extract values from a row.

May be derived for structs using #[derive(FromSqlRow)].

Example

#[derive(FromSqlRow)]
struct Person {
    age: i32,
    name: String,
    birthday: Option<Date<String>>,
}

Associated Constants

const COLUMN_COUNT: usize

Number of columns required to construct this type.

IMPORTANT: if not set correctly, extractors which depend on this value may produce errors.

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Required methods

fn from_row<R>(row: &R) -> Result<Self, Error> where
    R: Row, 

Extract values from a single row.

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Provided methods

fn from_row_multi<R>(rows: &[R]) -> Result<Vec<Self>, Error> where
    R: Row, 

Extract values from multiple rows.

Implementors of this trait may override this method to enable optimizations not possible in from_row by, for example, only looking up the indices of columns with a specific name once.

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Implementations on Foreign Types

impl<A> FromSqlRow for (A,) where
    A: for<'a> FromSql<'a> + Display, 

const COLUMN_COUNT: usize

fn from_row<R>(row: &R) -> Result<Self, Error> where
    R: Row, 

impl<A, B> FromSqlRow for (A, B) where
    A: for<'a> FromSql<'a> + Display,
    B: for<'a> FromSql<'a> + Display, 

const COLUMN_COUNT: usize

fn from_row<R>(row: &R) -> Result<Self, Error> where
    R: Row, 

impl<A, B, C> FromSqlRow for (A, B, C) where
    A: for<'a> FromSql<'a> + Display,
    B: for<'a> FromSql<'a> + Display,
    C: for<'a> FromSql<'a> + Display, 

const COLUMN_COUNT: usize

fn from_row<R>(row: &R) -> Result<Self, Error> where
    R: Row, 

impl<A, B, C, D> FromSqlRow for (A, B, C, D) where
    A: for<'a> FromSql<'a> + Display,
    B: for<'a> FromSql<'a> + Display,
    C: for<'a> FromSql<'a> + Display,
    D: for<'a> FromSql<'a> + Display, 

const COLUMN_COUNT: usize

fn from_row<R>(row: &R) -> Result<Self, Error> where
    R: Row, 

impl<A, B, C, D, E> FromSqlRow for (A, B, C, D, E) where
    A: for<'a> FromSql<'a> + Display,
    B: for<'a> FromSql<'a> + Display,
    C: for<'a> FromSql<'a> + Display,
    D: for<'a> FromSql<'a> + Display,
    E: for<'a> FromSql<'a> + Display, 

const COLUMN_COUNT: usize

fn from_row<R>(row: &R) -> Result<Self, Error> where
    R: Row, 

impl<A, B, C, D, E, F> FromSqlRow for (A, B, C, D, E, F) where
    A: for<'a> FromSql<'a> + Display,
    B: for<'a> FromSql<'a> + Display,
    C: for<'a> FromSql<'a> + Display,
    D: for<'a> FromSql<'a> + Display,
    E: for<'a> FromSql<'a> + Display,
    F: for<'a> FromSql<'a> + Display, 

const COLUMN_COUNT: usize

fn from_row<R>(row: &R) -> Result<Self, Error> where
    R: Row, 

impl<A, B, C, D, E, F, G> FromSqlRow for (A, B, C, D, E, F, G) where
    A: for<'a> FromSql<'a> + Display,
    B: for<'a> FromSql<'a> + Display,
    C: for<'a> FromSql<'a> + Display,
    D: for<'a> FromSql<'a> + Display,
    E: for<'a> FromSql<'a> + Display,
    F: for<'a> FromSql<'a> + Display,
    G: for<'a> FromSql<'a> + Display, 

const COLUMN_COUNT: usize

fn from_row<R>(row: &R) -> Result<Self, Error> where
    R: Row, 

impl<A, B, C, D, E, F, G, H> FromSqlRow for (A, B, C, D, E, F, G, H) where
    A: for<'a> FromSql<'a> + Display,
    B: for<'a> FromSql<'a> + Display,
    C: for<'a> FromSql<'a> + Display,
    D: for<'a> FromSql<'a> + Display,
    E: for<'a> FromSql<'a> + Display,
    F: for<'a> FromSql<'a> + Display,
    G: for<'a> FromSql<'a> + Display,
    H: for<'a> FromSql<'a> + Display, 

const COLUMN_COUNT: usize

fn from_row<R>(row: &R) -> Result<Self, Error> where
    R: Row, 

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Implementors

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