[][src]Struct diesel::query_builder::DeleteStatement

#[must_use =
  "Queries are only executed when calling `load`, `get_result` or similar."]pub struct DeleteStatement<T, U, Ret = NoReturningClause> { /* fields omitted */ }

Represents a SQL DELETE statement.

The type parameters on this struct represent:

Implementations

impl<T, U> DeleteStatement<T, U, NoReturningClause>[src]

pub fn filter<Predicate>(self, predicate: Predicate) -> Filter<Self, Predicate> where
    Self: FilterDsl<Predicate>, 
[src]

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);

pub fn into_boxed<'a, DB>(self) -> IntoBoxed<'a, Self, DB> where
    DB: Backend,
    Self: BoxedDsl<'a, DB>, 
[src]

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);

impl<T, U> DeleteStatement<T, U, NoReturningClause>[src]

pub fn returning<E>(
    self,
    returns: E
) -> DeleteStatement<T, U, ReturningClause<E>> where
    E: SelectableExpression<T>,
    DeleteStatement<T, U, ReturningClause<E>>: Query
[src]

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

impl<T, U> AsQuery for DeleteStatement<T, U, NoReturningClause> where
    T: Table,
    T::AllColumns: SelectableExpression<T>,
    DeleteStatement<T, U, ReturningClause<T::AllColumns>>: Query
[src]

type SqlType = <Self::Query as Query>::SqlType

The SQL type of Self::Query

type Query = DeleteStatement<T, U, ReturningClause<T::AllColumns>>

What kind of query does this type represent?

impl<'a, T, U, Ret, DB> BoxedDsl<'a, DB> for DeleteStatement<T, U, Ret> where
    U: Into<BoxedWhereClause<'a, DB>>, 
[src]

type Output = BoxedDeleteStatement<'a, DB, T, Ret>

The return type of internal_into_boxed

impl<T: Clone, U: Clone, Ret: Clone> Clone for DeleteStatement<T, U, Ret>[src]

impl<T: Copy, U: Copy, Ret: Copy> Copy for DeleteStatement<T, U, Ret>[src]

impl<T: Debug, U: Debug, Ret: Debug> Debug for DeleteStatement<T, U, Ret>[src]

impl<T, U, Ret, Predicate> FilterDsl<Predicate> for DeleteStatement<T, U, Ret> where
    U: WhereAnd<Predicate>,
    Predicate: AppearsOnTable<T>, 
[src]

type Output = DeleteStatement<T, U::Output, Ret>

The type returned by .filter.

impl<T, U, Ret> Query for DeleteStatement<T, U, ReturningClause<Ret>> where
    T: Table,
    Ret: SelectableExpression<T>, 
[src]

type SqlType = Ret::SqlType

The SQL type that this query represents. Read more

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>, 
[src]

impl<T: QueryId, U: QueryId, Ret: QueryId> QueryId for DeleteStatement<T, U, Ret>[src]

type QueryId = DeleteStatement<<T as QueryId>::QueryId, <U as QueryId>::QueryId, <Ret as QueryId>::QueryId>

A type which uniquely represents Self in a SQL query. Read more

impl<T, U, Ret, Conn> RunQueryDsl<Conn> for DeleteStatement<T, U, Ret>[src]

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

impl<T> Any for T where
    T: 'static + ?Sized
[src]

impl<T> AsQuery for T where
    T: Query
[src]

type SqlType = <T as Query>::SqlType

The SQL type of Self::Query

type Query = T

What kind of query does this type represent?

impl<T> Borrow<T> for T where
    T: ?Sized
[src]

impl<T> BorrowMut<T> for T where
    T: ?Sized
[src]

impl<'a, T, DB> BoxedDsl<'a, DB> for T where
    T: Table + AsQuery,
    <T as AsQuery>::Query: BoxedDsl<'a, DB>, 
[src]

type Output = <<T as AsQuery>::Query as BoxedDsl<'a, DB>>::Output

The return type of internal_into_boxed

impl<Conn, DB, T> ExecuteDsl<Conn, DB> for T where
    Conn: Connection<Backend = DB>,
    DB: Backend,
    T: QueryFragment<DB> + QueryId
[src]

impl<T, Predicate> FilterDsl<Predicate> for T where
    T: Table,
    <T as AsQuery>::Query: FilterDsl<Predicate>, 
[src]

type Output = <<T as AsQuery>::Query as FilterDsl<Predicate>>::Output

The type returned by .filter.

impl<T> From<T> for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 
[src]

impl<T> IntoSql for T[src]

impl<Conn, T, U> LoadQuery<Conn, U> for T where
    Conn: Connection,
    T: AsQuery + RunQueryDsl<Conn>,
    U: FromSqlRow<<T as AsQuery>::SqlType, <Conn as Connection>::Backend>,
    <T as AsQuery>::Query: QueryFragment<<Conn as Connection>::Backend>,
    <T as AsQuery>::Query: QueryId,
    <Conn as Connection>::Backend: QueryMetadata<<T as AsQuery>::SqlType>, 
[src]

impl<T, Conn> RunQueryDsl<Conn> for T where
    T: Table
[src]

impl<T> ToOwned for T where
    T: Clone
[src]

type Owned = T

The resulting type after obtaining ownership.

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 
[src]

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 
[src]

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

impl<V, T> VZip<V> for T where
    V: MultiLane<T>, 
[src]