Struct diesel::connection::statement_cache::StatementCache

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pub struct StatementCache<DB: Backend, Statement> { /* private fields */ }
Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.
Expand description

A prepared statement cache

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impl<DB, Statement> StatementCache<DB, Statement>

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pub fn new() -> Self

Create a new prepared statement cache

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pub fn len(&self) -> usize

Get the current length of the statement cache

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pub fn cached_statement<T, F>( &mut self, source: &T, backend: &DB, bind_types: &[DB::TypeMetadata], prepare_fn: F ) -> QueryResult<MaybeCached<'_, Statement>>
where T: QueryFragment<DB> + QueryId, F: FnOnce(&str, PrepareForCache) -> QueryResult<Statement>,

Prepare a query as prepared statement

This functions returns a prepared statement corresponding to the query passed as source with the bind values passed as bind_types. If the query is already cached inside this prepared statement cache the cached prepared statement will be returned, otherwise prepare_fn will be called to create a new prepared statement for this query source. The first parameter of the callback contains the query string, the second parameter indicates if the constructed prepared statement will be cached or not. See the module documentation for details about which statements are cached and which are not cached.

Auto Trait Implementations§

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impl<DB, Statement> Freeze for StatementCache<DB, Statement>

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impl<DB, Statement> RefUnwindSafe for StatementCache<DB, Statement>

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impl<DB, Statement> Send for StatementCache<DB, Statement>
where Statement: Send, <DB as TypeMetadata>::TypeMetadata: Send,

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impl<DB, Statement> Sync for StatementCache<DB, Statement>
where Statement: Sync, <DB as TypeMetadata>::TypeMetadata: Sync,

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impl<DB, Statement> Unpin for StatementCache<DB, Statement>
where Statement: Unpin, <DB as TypeMetadata>::TypeMetadata: Unpin,

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impl<DB, Statement> UnwindSafe for StatementCache<DB, Statement>
where Statement: UnwindSafe, <DB as TypeMetadata>::TypeMetadata: UnwindSafe,

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoSql for T

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fn into_sql<T>(self) -> AsExprOf<Self, T>

Convert self to an expression for Diesel’s query builder. Read more
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fn as_sql<'a, T>(&'a self) -> AsExprOf<&'a Self, T>

Convert &self to an expression for Diesel’s query builder. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V