pub struct StatementCache<DB: Backend, Statement> { /* private fields */ }
Expand description

A prepared statement cache

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impl<DB, Statement> StatementCache<DB, Statement>where DB: Backend, DB::TypeMetadata: Clone, DB::QueryBuilder: Default, StatementCacheKey<DB>: Hash + Eq,

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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.

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

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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 Twhere 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 Twhere 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 Twhere 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 Twhere 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>where Self: AsExpression<T> + Sized, T: SqlType + TypedExpressionType,

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>where &'a Self: AsExpression<T>, T: SqlType + TypedExpressionType,

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