Struct Expr 

pub struct Expr<'scope, T> { /* private fields */ }

A type representing an expression in the query, can be passed around on the rust side to wire things up

Implementations

impl<'scope, T> Expr<'scope, T>

pub fn lit(value: T) -> Self

where T: Into<Value>,

Construct a literal value from any value from any value that can be encoded.

pub fn equals(self, other: Self) -> Expr<'scope, bool>

impl<'scope> Expr<'scope, i32>

pub fn add(self, other: Self) -> Self

pub fn nextval(name: &str) -> Self

generate nextval('name'), this must be used within Query::evaluate for it to behave properly.

Example

use rust_rel8::{helper_tables::One, *};

query::<(Expr<i32>, Expr<i32>)>(|q| {
  let id = q.q(Query::evaluate(Expr::nextval("table_id_seq")));
  let v = q.q(Query::values([1, 2, 3].map(|a| One { a })));
  (id, v.a)
});

Trait Implementations

impl<'scope, T: Clone> Clone for Expr<'scope, T>

fn clone(&self) -> Expr<'scope, T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> ForLifetimeTable for Expr<'static, T>

type Of<'lt> = Expr<'lt, T> where T: 'lt

impl<T> ShortenLifetime for Expr<'static, T>

type Shortened<'small> = Expr<'small, T> where Self: 'small

fn shorten_lifetime<'small, 'large: 'small>(self) -> Self::Shortened<'small>

where Self: 'large,

Shorten a lifetime, normally rust does this automatically, but if the lifetime is invariant due to being used in a Gat or trait, we need to do it manually.

impl<'scope, T> Table<'scope> for Expr<'scope, T>

type Nullify = Expr<'scope, Option<T>>

type Result = T

fn visit(&self, f: &mut impl FnMut(&ErasedExpr))

Visit each expr in the table.

fn visit_mut(&mut self, f: &mut impl FnMut(&mut ErasedExpr))

Visit each expr in the table, with a mutable reference.

fn nullify(self) -> Self::Nullify

impl<T: for<'r> Decode<'r, Any>> TableLoaderSqlx for Expr<'static, T>

Available on crate feature sqlx only.

fn load<'a>( &self, values: &mut impl Iterator<Item = AnyValueRef<'a>>, ) -> Self::Result

Load the table given an iterator over a row’s values

fn skip<'a>(&self, values: &mut impl Iterator<Item = AnyValueRef<'a>>)

discard N columns from the iterator ofer a row This is used when this value was discarded by a MaybeTable.