Struct ReturningQuerySource 

pub struct ReturningQuerySource<StmtKind, T>(/* private fields */);

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

Synthetic query source used as the QS parameter of SelectableExpression / AppearsOnTable when type-checking RETURNING clauses.

StmtKind is one of the marker structs above; T is the table that the INSERT/UPDATE/DELETE is acting on.

Trait Implementations

impl<T> AppearsInFromClause<ReturningQuerySource<OldIdent, T>> for ReturningQuerySource<UpdateStmt, T>

Available on crate feature postgres_backend only.

There is an old. for T in ReturningQuerySource<UpdateStmt, T>

type Count = Once

How many times does QS appear in Self?

impl<T> AppearsInFromClause<ReturningQuerySource<OldIdent, T>> for ReturningQuerySource<InsertStmtWithOnConflictDoUpdate, T>

Available on crate feature postgres_backend only.

There is an old. for T in ReturningQuerySource<InsertStmtWithOnConflictDoUpdate, T>

type Count = Once

How many times does QS appear in Self?

impl<StmtKind, T1, T2> AppearsInFromClause<T1> for ReturningQuerySource<StmtKind, T2>

where T1: TableNotEqual<T2> + QueryRelation, T2: QueryRelation,

type Count = Never

How many times does QS appear in Self?

impl<'a, QS, ST, DB, GB, IsAggregate, StmtKind> AppearsOnTable<ReturningQuerySource<StmtKind, QS>> for Box<dyn BoxableExpression<QS, DB, GB, IsAggregate, SqlType = ST> + 'a>

where Box<dyn BoxableExpression<QS, DB, GB, IsAggregate, SqlType = ST> + 'a>: Expression,

See comment on SelectableExpression impl above.

impl<StmtKind: Clone, T: Clone> Clone for ReturningQuerySource<StmtKind, T>

fn clone(&self) -> ReturningQuerySource<StmtKind, T>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<StmtKind: Copy, T: Copy> Copy for ReturningQuerySource<StmtKind, T>

impl<StmtKind: Debug, T: Debug> Debug for ReturningQuerySource<StmtKind, T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<StmtKind, T> QuerySource for ReturningQuerySource<StmtKind, T>

where T: QuerySource + Default, T::DefaultSelection: SelectableExpression<Self>,

type FromClause = <T as QuerySource>::FromClause

The type returned by from_clause

type DefaultSelection = <T as QuerySource>::DefaultSelection

The type returned by default_selection

fn from_clause(&self) -> Self::FromClause

The actual FROM clause of this type. This is typically only called in QueryFragment implementations.

fn default_selection(&self) -> Self::DefaultSelection

The default select clause of this type, which should be used if no select clause was explicitly specified. This should always be a tuple of all the desired columns, not star

impl<'a, QS, ST, DB, GB, IsAggregate, StmtKind> SelectableExpression<ReturningQuerySource<StmtKind, QS>> for Box<dyn BoxableExpression<QS, DB, GB, IsAggregate, SqlType = ST> + 'a>

where Box<dyn BoxableExpression<QS, DB, GB, IsAggregate, SqlType = ST> + 'a>: Expression,

Make Box<dyn BoxableExpression<table>> be SelectableExpression in returning clauses. This is necessary for backwards-compatibility.

Unfortunately we cannot implement this directly for dyn BoxableExpression (and rely on our existing generic impls for Box<T>) because the compiler complains that there is already an automatic implementation of SelectableExpression for dyn BoxableExpression, even though the QS type is different. As a workaround, we implement it for Box<dyn BoxableExpression<table>>, which should cover for most users.