Struct StatementCache 

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

Available on crate feature i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

A prepared statement cache

Implementations

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

where DB: Backend + 'static, Statement: Send + 'static, DB::TypeMetadata: Send + Clone, DB::QueryBuilder: Default, StatementCacheKey<DB>: Hash + Eq,

pub fn new() -> Self

Create a new prepared statement cache using CacheSize::Unbounded as caching strategy.

pub fn set_cache_size(&mut self, size: CacheSize)

Set caching strategy from predefined implementations

pub fn cached_statement<'a, T, R, C>( &'a mut self, source: &T, backend: &DB, bind_types: &[DB::TypeMetadata], conn: C, prepare_fn: fn(C, &str, PrepareForCache, &[DB::TypeMetadata]) -> R, instrumentation: &mut dyn Instrumentation, ) -> R::Return<'a>

where T: QueryFragment<DB> + QueryId, R: StatementCallbackReturnType<Statement, C> + 'a,

Available on crate features i-implement-a-third-party-backend-and-opt-into-breaking-changes or sqlite or mysql only.

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.

pub fn cached_statement_non_generic<'a, R, C>( &'a mut self, maybe_type_id: Option<TypeId>, source: &dyn QueryFragmentForCachedStatement<DB>, backend: &DB, bind_types: &[DB::TypeMetadata], conn: C, prepare_fn: fn(C, &str, PrepareForCache, &[DB::TypeMetadata]) -> R, instrumentation: &mut dyn Instrumentation, ) -> R::Return<'a>

where R: StatementCallbackReturnType<Statement, C> + 'a,

Prepare a query as prepared statement

This function closely mirrors Self::cached_statement but eliminates the generic query type in favour of a trait object

This can be easier to use in situations where you already turned the query type into a concrete SQL string