Struct diesel::query_builder::DeleteStatement
source · pub struct DeleteStatement<T: QuerySource, U, Ret = NoReturningClause> { /* private fields */ }
Expand description
Represents a SQL DELETE
statement.
The type parameters on this struct represent:
T
: The table we are deleting from.U
: TheWHERE
clause of this query. The exact types used to represent this are private, and you should not make any assumptions about them.Ret
: TheRETURNING
clause of this query. The exact types used to represent this are private. You can safely rely on the default type representing the lack of aRETURNING
clause.
Implementations§
source§impl<T: QuerySource, U> DeleteStatement<T, U, NoReturningClause>
impl<T: QuerySource, U> DeleteStatement<T, U, NoReturningClause>
sourcepub fn filter<Predicate>(self, predicate: Predicate) -> Filter<Self, Predicate>where
Self: FilterDsl<Predicate>,
pub fn filter<Predicate>(self, predicate: Predicate) -> Filter<Self, Predicate>where
Self: FilterDsl<Predicate>,
Adds the given predicate to the WHERE
clause of the statement being
constructed.
If there is already a WHERE
clause, the predicate will be appended
with AND
. There is no difference in behavior between
delete(table.filter(x))
and delete(table).filter(x)
.
§Example
let deleted_rows = diesel::delete(users)
.filter(name.eq("Sean"))
.execute(connection);
assert_eq!(Ok(1), deleted_rows);
let expected_names = vec!["Tess".to_string()];
let names = users.select(name).load(connection);
assert_eq!(Ok(expected_names), names);
sourcepub fn or_filter<Predicate>(
self,
predicate: Predicate,
) -> OrFilter<Self, Predicate>where
Self: OrFilterDsl<Predicate>,
pub fn or_filter<Predicate>(
self,
predicate: Predicate,
) -> OrFilter<Self, Predicate>where
Self: OrFilterDsl<Predicate>,
Adds to the WHERE
clause of a query using OR
If there is already a WHERE
clause, the result will be (old OR new)
.
Calling foo.filter(bar).or_filter(baz)
is identical to foo.filter(bar.or(baz))
.
However, the second form is much harder to do dynamically.
§Example
let deleted_rows = diesel::delete(users)
.filter(name.eq("Sean"))
.or_filter(name.eq("Tess"))
.execute(connection);
assert_eq!(Ok(2), deleted_rows);
let num_users = users.count().first(connection);
assert_eq!(Ok(0), num_users);
sourcepub fn into_boxed<'a, DB>(self) -> IntoBoxed<'a, Self, DB>
pub fn into_boxed<'a, DB>(self) -> IntoBoxed<'a, Self, DB>
Boxes the WHERE
clause of this delete statement.
This is useful for cases where you want to conditionally modify a query, but need the type to remain the same. The backend must be specified as part of this. It is not possible to box a query and have it be useable on multiple backends.
A boxed query will incur a minor performance penalty, as the query builder can no longer be inlined by the compiler. For most applications this cost will be minimal.
§Example
let mut query = diesel::delete(users)
.into_boxed();
if params["sean_has_been_a_jerk"] {
query = query.filter(name.eq("Sean"));
}
let deleted_rows = query.execute(connection)?;
assert_eq!(1, deleted_rows);
let expected_names = vec!["Tess"];
let names = users.select(name).load::<String>(connection)?;
assert_eq!(expected_names, names);
source§impl<T: QuerySource, U> DeleteStatement<T, U, NoReturningClause>
impl<T: QuerySource, U> DeleteStatement<T, U, NoReturningClause>
sourcepub fn returning<E>(
self,
returns: E,
) -> DeleteStatement<T, U, ReturningClause<E>>
pub fn returning<E>( self, returns: E, ) -> DeleteStatement<T, U, ReturningClause<E>>
Trait Implementations§
source§impl<T, U> AsQuery for DeleteStatement<T, U, NoReturningClause>where
T: Table,
T::AllColumns: SelectableExpression<T>,
DeleteStatement<T, U, ReturningClause<T::AllColumns>>: Query,
impl<T, U> AsQuery for DeleteStatement<T, U, NoReturningClause>where
T: Table,
T::AllColumns: SelectableExpression<T>,
DeleteStatement<T, U, ReturningClause<T::AllColumns>>: Query,
source§type SqlType = <<DeleteStatement<T, U> as AsQuery>::Query as Query>::SqlType
type SqlType = <<DeleteStatement<T, U> as AsQuery>::Query as Query>::SqlType
Self::Query
source§type Query = DeleteStatement<T, U, ReturningClause<<T as Table>::AllColumns>>
type Query = DeleteStatement<T, U, ReturningClause<<T as Table>::AllColumns>>
source§impl<'a, T, U, Ret, DB> BoxedDsl<'a, DB> for DeleteStatement<T, U, Ret>where
U: Into<BoxedWhereClause<'a, DB>>,
T: QuerySource,
impl<'a, T, U, Ret, DB> BoxedDsl<'a, DB> for DeleteStatement<T, U, Ret>where
U: Into<BoxedWhereClause<'a, DB>>,
T: QuerySource,
source§type Output = DeleteStatement<T, BoxedWhereClause<'a, DB>, Ret>
type Output = DeleteStatement<T, BoxedWhereClause<'a, DB>, Ret>
internal_into_boxed
source§fn internal_into_boxed(self) -> Self::Output
fn internal_into_boxed(self) -> Self::Output
source§impl<T, U, Ret> Clone for DeleteStatement<T, U, Ret>
impl<T, U, Ret> Clone for DeleteStatement<T, U, Ret>
source§impl<T, U, Ret> Debug for DeleteStatement<T, U, Ret>
impl<T, U, Ret> Debug for DeleteStatement<T, U, Ret>
source§impl<T, U, Ret, Predicate> FilterDsl<Predicate> for DeleteStatement<T, U, Ret>where
U: WhereAnd<Predicate>,
Predicate: AppearsOnTable<T>,
T: QuerySource,
impl<T, U, Ret, Predicate> FilterDsl<Predicate> for DeleteStatement<T, U, Ret>where
U: WhereAnd<Predicate>,
Predicate: AppearsOnTable<T>,
T: QuerySource,
source§impl<T, U, Ret, Predicate> OrFilterDsl<Predicate> for DeleteStatement<T, U, Ret>where
T: QuerySource,
U: WhereOr<Predicate>,
Predicate: AppearsOnTable<T>,
impl<T, U, Ret, Predicate> OrFilterDsl<Predicate> for DeleteStatement<T, U, Ret>where
T: QuerySource,
U: WhereOr<Predicate>,
Predicate: AppearsOnTable<T>,
source§impl<T, U, Ret> Query for DeleteStatement<T, U, ReturningClause<Ret>>where
T: Table,
Ret: SelectableExpression<T>,
impl<T, U, Ret> Query for DeleteStatement<T, U, ReturningClause<Ret>>where
T: Table,
Ret: SelectableExpression<T>,
source§impl<T, U, Ret, DB> QueryFragment<DB> for DeleteStatement<T, U, Ret>where
DB: Backend + DieselReserveSpecialization,
T: Table,
FromClause<T>: QueryFragment<DB>,
U: QueryFragment<DB>,
Ret: QueryFragment<DB>,
impl<T, U, Ret, DB> QueryFragment<DB> for DeleteStatement<T, U, Ret>where
DB: Backend + DieselReserveSpecialization,
T: Table,
FromClause<T>: QueryFragment<DB>,
U: QueryFragment<DB>,
Ret: QueryFragment<DB>,
source§fn walk_ast<'b>(&'b self, out: AstPass<'_, 'b, DB>) -> QueryResult<()>
fn walk_ast<'b>(&'b self, out: AstPass<'_, 'b, DB>) -> QueryResult<()>
QueryFragment
for all passes. Read moresource§fn to_sql(&self, out: &mut DB::QueryBuilder, backend: &DB) -> QueryResult<()>
fn to_sql(&self, out: &mut DB::QueryBuilder, backend: &DB) -> QueryResult<()>
i-implement-a-third-party-backend-and-opt-into-breaking-changes
only.QueryFragment
to its SQL representation. Read moresource§fn collect_binds<'b>(
&'b self,
out: &mut DB::BindCollector<'b>,
metadata_lookup: &mut DB::MetadataLookup,
backend: &'b DB,
) -> QueryResult<()>
fn collect_binds<'b>( &'b self, out: &mut DB::BindCollector<'b>, metadata_lookup: &mut DB::MetadataLookup, backend: &'b DB, ) -> QueryResult<()>
i-implement-a-third-party-backend-and-opt-into-breaking-changes
only.source§fn is_safe_to_cache_prepared(&self, backend: &DB) -> QueryResult<bool>
fn is_safe_to_cache_prepared(&self, backend: &DB) -> QueryResult<bool>
i-implement-a-third-party-backend-and-opt-into-breaking-changes
only.source§impl<T, U, Ret> QueryId for DeleteStatement<T, U, Ret>
impl<T, U, Ret> QueryId for DeleteStatement<T, U, Ret>
source§impl<T, U, Ret, Conn> RunQueryDsl<Conn> for DeleteStatement<T, U, Ret>where
T: QuerySource,
impl<T, U, Ret, Conn> RunQueryDsl<Conn> for DeleteStatement<T, U, Ret>where
T: QuerySource,
source§fn load<'query, U>(self, conn: &mut Conn) -> QueryResult<Vec<U>>where
Self: LoadQuery<'query, Conn, U>,
fn load<'query, U>(self, conn: &mut Conn) -> QueryResult<Vec<U>>where
Self: LoadQuery<'query, Conn, U>,
source§fn load_iter<'conn, 'query: 'conn, U, B>(
self,
conn: &'conn mut Conn,
) -> QueryResult<Self::RowIter<'conn>>where
U: 'conn,
Self: LoadQuery<'query, Conn, U, B> + 'conn,
fn load_iter<'conn, 'query: 'conn, U, B>(
self,
conn: &'conn mut Conn,
) -> QueryResult<Self::RowIter<'conn>>where
U: 'conn,
Self: LoadQuery<'query, Conn, U, B> + 'conn,
source§fn get_result<'query, U>(self, conn: &mut Conn) -> QueryResult<U>where
Self: LoadQuery<'query, Conn, U>,
fn get_result<'query, U>(self, conn: &mut Conn) -> QueryResult<U>where
Self: LoadQuery<'query, Conn, U>,
source§fn get_results<'query, U>(self, conn: &mut Conn) -> QueryResult<Vec<U>>where
Self: LoadQuery<'query, Conn, U>,
fn get_results<'query, U>(self, conn: &mut Conn) -> QueryResult<Vec<U>>where
Self: LoadQuery<'query, Conn, U>,
Vec
with the affected rows. Read moreAuto Trait Implementations§
impl<T, U, Ret> Freeze for DeleteStatement<T, U, Ret>
impl<T, U, Ret> RefUnwindSafe for DeleteStatement<T, U, Ret>where
U: RefUnwindSafe,
Ret: RefUnwindSafe,
T: RefUnwindSafe,
<T as QuerySource>::FromClause: RefUnwindSafe,
impl<T, U, Ret> Send for DeleteStatement<T, U, Ret>
impl<T, U, Ret> Sync for DeleteStatement<T, U, Ret>
impl<T, U, Ret> Unpin for DeleteStatement<T, U, Ret>
impl<T, U, Ret> UnwindSafe for DeleteStatement<T, U, Ret>
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
source§unsafe fn clone_to_uninit(&self, dst: *mut T)
unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)