Struct diesel::query_builder::DeleteStatement
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pub struct DeleteStatement<T, U, Ret = NoReturningClause> { /* fields omitted */ }
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.
Methods
impl<T, U> DeleteStatement<T, U, NoReturningClause>
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fn filter<Predicate>(self, predicate: Predicate) -> Filter<Self, Predicate> where
Self: FilterDsl<Predicate>,
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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);
impl<T, U> DeleteStatement<T, U, NoReturningClause>
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fn returning<E>(self, returns: E) -> DeleteStatement<T, U, ReturningClause<E>> where
E: SelectableExpression<T>,
DeleteStatement<T, U, ReturningClause<E>>: Query,
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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
impl<T: Debug, U: Debug, Ret: Debug> Debug for DeleteStatement<T, U, Ret>
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impl<T, U, Ret, Predicate> FilterDsl<Predicate> for DeleteStatement<T, U, Ret> where
U: WhereAnd<Predicate>,
Predicate: AppearsOnTable<T>,
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U: WhereAnd<Predicate>,
Predicate: AppearsOnTable<T>,
type Output = DeleteStatement<T, U::Output, Ret>
The type returned by .filter
.
fn filter(self, predicate: Predicate) -> Self::Output
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See the trait documentation.
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>,
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DB: Backend,
T: Table,
T::FromClause: QueryFragment<DB>,
U: QueryFragment<DB>,
Ret: QueryFragment<DB>,
fn walk_ast(&self, out: AstPass<DB>) -> QueryResult<()>
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Walk over this QueryFragment
for all passes. Read more
fn to_sql(&self, out: &mut DB::QueryBuilder) -> QueryResult<()>
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Converts this QueryFragment
to its SQL representation. Read more
fn collect_binds(
&self,
out: &mut DB::BindCollector,
metadata_lookup: &DB::MetadataLookup
) -> QueryResult<()>
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&self,
out: &mut DB::BindCollector,
metadata_lookup: &DB::MetadataLookup
) -> QueryResult<()>
Serializes all bind parameters in this query. Read more
fn is_safe_to_cache_prepared(&self) -> QueryResult<bool>
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Is this query safe to store in the prepared statement cache? Read more
impl<T, U, Ret> QueryId for DeleteStatement<T, U, Ret> where
T: QueryId,
U: QueryId,
Ret: QueryId,
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T: QueryId,
U: QueryId,
Ret: QueryId,
type QueryId = DeleteStatement<T::QueryId, U::QueryId, Ret::QueryId>
A type which uniquely represents Self
in a SQL query. Read more
const HAS_STATIC_QUERY_ID: bool
HAS_STATIC_QUERY_ID: bool = <T>::HAS_STATIC_QUERY_ID && <U>::HAS_STATIC_QUERY_ID && <Ret>::HAS_STATIC_QUERY_ID && true
Can the SQL generated by Self
be uniquely identified by its type? Read more
fn query_id() -> Option<TypeId>
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Returns the type id of Self::QueryId
if Self::HAS_STATIC_QUERY_ID
. Returns None
otherwise. Read more
impl<T, U> AsQuery for DeleteStatement<T, U, NoReturningClause> where
T: Table,
T::AllColumns: SelectableExpression<T>,
DeleteStatement<T, U, ReturningClause<T::AllColumns>>: Query,
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T: Table,
T::AllColumns: SelectableExpression<T>,
DeleteStatement<T, U, ReturningClause<T::AllColumns>>: Query,
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?
fn as_query(self) -> Self::Query
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Converts a type which semantically represents a SQL query into the actual query being executed. See the trait level docs for more. Read more
impl<T, U, Ret> Query for DeleteStatement<T, U, ReturningClause<Ret>> where
T: Table,
Ret: SelectableExpression<T>,
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T: Table,
Ret: SelectableExpression<T>,
impl<T, U, Ret, Conn> RunQueryDsl<Conn> for DeleteStatement<T, U, Ret>
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fn execute(self, conn: &Conn) -> QueryResult<usize> where
Conn: Connection,
Self: ExecuteDsl<Conn>,
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Conn: Connection,
Self: ExecuteDsl<Conn>,
Executes the given command, returning the number of rows affected. Read more
fn load<U>(self, conn: &Conn) -> QueryResult<Vec<U>> where
Self: LoadQuery<Conn, U>,
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Self: LoadQuery<Conn, U>,
Executes the given query, returning a Vec
with the returned rows. Read more
fn get_result<U>(self, conn: &Conn) -> QueryResult<U> where
Self: LoadQuery<Conn, U>,
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Self: LoadQuery<Conn, U>,
Runs the command, and returns the affected row. Read more
fn get_results<U>(self, conn: &Conn) -> QueryResult<Vec<U>> where
Self: LoadQuery<Conn, U>,
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Self: LoadQuery<Conn, U>,
Runs the command, returning an Vec
with the affected rows. Read more
fn first<U>(self, conn: &Conn) -> QueryResult<U> where
Self: LimitDsl,
Limit<Self>: LoadQuery<Conn, U>,
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Self: LimitDsl,
Limit<Self>: LoadQuery<Conn, U>,
Attempts to load a single record. Read more