Struct ConflictUpdate 

pub struct ConflictUpdate<D, T> { /* private fields */ }

The DO UPDATE half of an upsert: everything an UPDATE assigns, plus excluded, plus the WHERE that decides whether the update fires at all. An Assignments converts into one, so a request-shaped patch reaches an upsert as it always did; the reverse doesn’t exist, which is what keeps a list naming the proposed row out of a statement that has none.

It carries D for the reason Predicate does: its WHERE is a condition like any other, and a condition pinned to one dialect must not reach a statement of another. The statement it is passed to says which dialect that is, so a value built inline needs no annotation. One bound to a let and never used does.

Implementations

impl<D, T: Table> ConflictUpdate<D, T>

pub fn set_to<C, V, Idxs>(_column: Column<C>, value: V) -> Self

where C: ColumnKey<Table = T> + Writable, V: IntoExpr, V::Sql: AssignsTo<C::Sql>, ConflictScope<T>: Superset<V::Req, Idxs>,

column = <expression>, over the conflicting row and the proposed one. This is Assignments::set_to with the wider scope.

pub fn and_set_to<C, V, Idxs>(self, _column: Column<C>, value: V) -> Self

where C: ColumnKey<Table = T> + Writable, V: IntoExpr, V::Sql: AssignsTo<C::Sql>, ConflictScope<T>: Superset<V::Req, Idxs>,

One more of them.

pub fn filter<C: Condition<D, ConflictScope<T>, Idxs>, Idxs>( self, cond: C, ) -> Self

DO UPDATE SET .. WHERE <condition>: which conflicting rows the update actually touches, over the conflicting row and the proposed one. A row the condition rejects is left as it is and is not counted, so a one-row upsert’s rows_affected() answers “did this write anything” rather than always being 1. It counts the rows a statement wrote, not the branch each took: a multi-row upsert’s count still folds inserts together with updates, and only zero says nothing happened.

A different clause from the one partial_index carries: that one only picks which index the conflict is inferred against.

pub fn filter_all( self, conds: impl IntoIterator<Item = Predicate<D, ConflictScope<T>>>, ) -> Self

AND-folds a runtime-length collection of discharged conditions, the same way Update::filter_all does.

pub fn correlated<S, InnerSel>( &self, source: S, selection: InnerSel, ) -> Select<D, Cons<TableSlot<S::Table, NotNull>, ConflictScope<T>>, InnerSel, ConflictScope<T>>

where S: JoinSource<D>,

A correlated subquery over the rows this action sees. It is the same EXISTS Update::correlated builds, against the conflicting row and the proposed one.

Trait Implementations

impl<D, T> From<Assignments<T>> for ConflictUpdate<D, T>

fn from(sets: Assignments<T>) -> Self

Converts to this type from the input type.