Struct diesel::query_builder::DeleteStatement
source · [−]pub struct DeleteStatement<T, 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
sourceimpl<T, U> DeleteStatement<T, U, NoReturningClause>
impl<T, 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 into_boxed<'a, DB>(self) -> IntoBoxed<'a, Self, DB> where
DB: Backend,
Self: BoxedDsl<'a, DB>,
pub fn into_boxed<'a, DB>(self) -> IntoBoxed<'a, Self, DB> where
DB: Backend,
Self: BoxedDsl<'a, 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);
sourceimpl<T, U> DeleteStatement<T, U, NoReturningClause>
impl<T, U> DeleteStatement<T, U, NoReturningClause>
sourcepub fn returning<E>(
self,
returns: E
) -> DeleteStatement<T, U, ReturningClause<E>> where
E: SelectableExpression<T>,
DeleteStatement<T, U, ReturningClause<E>>: Query,
pub fn returning<E>(
self,
returns: E
) -> DeleteStatement<T, U, ReturningClause<E>> where
E: SelectableExpression<T>,
DeleteStatement<T, U, ReturningClause<E>>: Query,
Specify what expression is returned after execution of the delete
.
Examples
Deleting a record:
let deleted_name = diesel::delete(users.filter(name.eq("Sean")))
.returning(name)
.get_result(&connection);
assert_eq!(Ok("Sean".to_string()), deleted_name);
Trait Implementations
sourceimpl<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,
type Query = DeleteStatement<T, U, ReturningClause<T::AllColumns>>
type Query = DeleteStatement<T, U, ReturningClause<T::AllColumns>>
What kind of query does this type represent?
sourceimpl<'a, T, U, Ret, DB> BoxedDsl<'a, DB> for DeleteStatement<T, U, Ret> where
U: Into<BoxedWhereClause<'a, DB>>,
impl<'a, T, U, Ret, DB> BoxedDsl<'a, DB> for DeleteStatement<T, U, Ret> where
U: Into<BoxedWhereClause<'a, DB>>,
type Output = BoxedDeleteStatement<'a, DB, T, Ret>
type Output = BoxedDeleteStatement<'a, DB, T, Ret>
The return type of internal_into_boxed
sourcefn internal_into_boxed(self) -> Self::Output
fn internal_into_boxed(self) -> Self::Output
See the trait documentation.
sourceimpl<T: Clone, U: Clone, Ret: Clone> Clone for DeleteStatement<T, U, Ret>
impl<T: Clone, U: Clone, Ret: Clone> Clone for DeleteStatement<T, U, Ret>
sourcefn clone(&self) -> DeleteStatement<T, U, Ret>
fn clone(&self) -> DeleteStatement<T, U, Ret>
Returns a copy of the value. Read more
1.0.0 · sourcefn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
sourceimpl<T, U, Ret, Predicate> FilterDsl<Predicate> for DeleteStatement<T, U, Ret> where
U: WhereAnd<Predicate>,
Predicate: AppearsOnTable<T>,
impl<T, U, Ret, Predicate> FilterDsl<Predicate> for DeleteStatement<T, U, Ret> where
U: WhereAnd<Predicate>,
Predicate: AppearsOnTable<T>,
type Output = DeleteStatement<T, U::Output, Ret>
type Output = DeleteStatement<T, U::Output, Ret>
The type returned by .filter
.
sourceimpl<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>,
sourceimpl<T, U, Ret, DB> QueryFragment<DB> for DeleteStatement<T, U, Ret> where
DB: Backend,
T: Table,
T::FromClause: QueryFragment<DB>,
U: QueryFragment<DB>,
Ret: QueryFragment<DB>,
impl<T, U, Ret, DB> QueryFragment<DB> for DeleteStatement<T, U, Ret> where
DB: Backend,
T: Table,
T::FromClause: QueryFragment<DB>,
U: QueryFragment<DB>,
Ret: QueryFragment<DB>,
sourcefn walk_ast(&self, out: AstPass<'_, DB>) -> QueryResult<()>
fn walk_ast(&self, out: AstPass<'_, DB>) -> QueryResult<()>
Walk over this QueryFragment
for all passes. Read more
sourcefn to_sql(&self, out: &mut DB::QueryBuilder) -> QueryResult<()>
fn to_sql(&self, out: &mut DB::QueryBuilder) -> QueryResult<()>
Converts this QueryFragment
to its SQL representation. Read more
sourcefn collect_binds(
&self,
out: &mut DB::BindCollector,
metadata_lookup: &DB::MetadataLookup
) -> QueryResult<()>
fn collect_binds(
&self,
out: &mut DB::BindCollector,
metadata_lookup: &DB::MetadataLookup
) -> QueryResult<()>
Serializes all bind parameters in this query. Read more
sourcefn is_safe_to_cache_prepared(&self) -> QueryResult<bool>
fn is_safe_to_cache_prepared(&self) -> QueryResult<bool>
Is this query safe to store in the prepared statement cache? Read more
sourceimpl<T: QueryId, U: QueryId, Ret: QueryId> QueryId for DeleteStatement<T, U, Ret>
impl<T: QueryId, U: QueryId, Ret: QueryId> QueryId for DeleteStatement<T, U, Ret>
sourceimpl<T, U, Ret, Conn> RunQueryDsl<Conn> for DeleteStatement<T, U, Ret>
impl<T, U, Ret, Conn> RunQueryDsl<Conn> for DeleteStatement<T, U, Ret>
sourcefn execute(self, conn: &Conn) -> QueryResult<usize> where
Conn: Connection,
Self: ExecuteDsl<Conn>,
fn execute(self, conn: &Conn) -> QueryResult<usize> where
Conn: Connection,
Self: ExecuteDsl<Conn>,
Executes the given command, returning the number of rows affected. Read more
sourcefn load<U>(self, conn: &Conn) -> QueryResult<Vec<U>> where
Self: LoadQuery<Conn, U>,
fn load<U>(self, conn: &Conn) -> QueryResult<Vec<U>> where
Self: LoadQuery<Conn, U>,
Executes the given query, returning a Vec
with the returned rows. Read more
sourcefn get_result<U>(self, conn: &Conn) -> QueryResult<U> where
Self: LoadQuery<Conn, U>,
fn get_result<U>(self, conn: &Conn) -> QueryResult<U> where
Self: LoadQuery<Conn, U>,
Runs the command, and returns the affected row. Read more
sourcefn get_results<U>(self, conn: &Conn) -> QueryResult<Vec<U>> where
Self: LoadQuery<Conn, U>,
fn get_results<U>(self, conn: &Conn) -> QueryResult<Vec<U>> where
Self: LoadQuery<Conn, U>,
Runs the command, returning an Vec
with the affected rows. Read more
impl<T: Copy, U: Copy, Ret: Copy> Copy for DeleteStatement<T, U, Ret>
Auto Trait Implementations
impl<T, U, Ret> RefUnwindSafe for DeleteStatement<T, U, Ret> where
Ret: RefUnwindSafe,
T: RefUnwindSafe,
U: RefUnwindSafe,
impl<T, U, Ret> Send for DeleteStatement<T, U, Ret> where
Ret: Send,
T: Send,
U: Send,
impl<T, U, Ret> Sync for DeleteStatement<T, U, Ret> where
Ret: Sync,
T: Sync,
U: Sync,
impl<T, U, Ret> Unpin for DeleteStatement<T, U, Ret> where
Ret: Unpin,
T: Unpin,
U: Unpin,
impl<T, U, Ret> UnwindSafe for DeleteStatement<T, U, Ret> where
Ret: UnwindSafe,
T: UnwindSafe,
U: UnwindSafe,
Blanket Implementations
sourceimpl<T> AsQuery for T where
T: Query,
impl<T> AsQuery for T where
T: Query,
type Query = Self
type Query = Self
What kind of query does this type represent?
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcepub fn borrow_mut(&mut self) -> &mut T
pub fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<Conn, DB, T> ExecuteDsl<Conn, DB> for T where
Conn: Connection<Backend = DB>,
DB: Backend,
T: QueryFragment<DB> + QueryId,
impl<Conn, DB, T> ExecuteDsl<Conn, DB> for T where
Conn: Connection<Backend = DB>,
DB: Backend,
T: QueryFragment<DB> + QueryId,
sourcefn execute(query: Self, conn: &Conn) -> QueryResult<usize>
fn execute(query: Self, conn: &Conn) -> QueryResult<usize>
Execute this command
sourceimpl<T> IntoSql for T
impl<T> IntoSql for T
sourceimpl<T> ToOwned for T where
T: Clone,
impl<T> ToOwned for T where
T: Clone,
type Owned = T
type Owned = T
The resulting type after obtaining ownership.
sourcepub fn to_owned(&self) -> T
pub fn to_owned(&self) -> T
Creates owned data from borrowed data, usually by cloning. Read more
sourcepub fn clone_into(&self, target: &mut T)
pub fn clone_into(&self, target: &mut T)
toowned_clone_into
)Uses borrowed data to replace owned data, usually by cloning. Read more