Enum diesel::connection::statement_cache::StatementCacheKey

pub enum StatementCacheKey<DB: Backend> {
    Type(TypeId),
    Sql {
        sql: String,
        bind_types: Vec<DB::TypeMetadata>,
    },
}

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

The lookup key used by StatementCache internally

This can contain either a at compile time known type id (representing a statically known query) or a at runtime calculated query string + parameter types (for queries that may change depending on their parameters)

Variants

Type(TypeId)

Represents a at compile time known query

Calculated via QueryId::QueryId

Sql

Represents a dynamically constructed query

This variant is used if QueryId::HAS_STATIC_QUERY_ID is false and AstPass::unsafe_to_cache_prepared is not called for a given query.

Fields

sql: String

contains the sql query string

bind_types: Vec<DB::TypeMetadata>

contains the types of any bind parameter passed to the query

Implementations

impl<DB> StatementCacheKey<DB>

where DB: Backend, DB::QueryBuilder: Default, DB::TypeMetadata: Clone,

pub fn for_source( maybe_type_id: Option<TypeId>, source: &dyn QueryFragmentForCachedStatement<DB>, bind_types: &[DB::TypeMetadata], backend: &DB ) -> QueryResult<Self>

Create a new statement cache key for the given query source

pub fn sql( &self, source: &dyn QueryFragmentForCachedStatement<DB>, backend: &DB ) -> QueryResult<Cow<'_, str>>

Get the sql for a given query source based

This is an optimization that may skip constructing the query string twice if it’s already part of the current cache key

Trait Implementations

impl<DB: Hash + Backend> Hash for StatementCacheKey<DB>

where DB::TypeMetadata: Hash,

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<DB: PartialEq + Backend> PartialEq for StatementCacheKey<DB>

where DB::TypeMetadata: PartialEq,

fn eq(&self, other: &StatementCacheKey<DB>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<DB: Eq + Backend> Eq for StatementCacheKey<DB>

where DB::TypeMetadata: Eq,

impl<DB: Backend> StructuralPartialEq for StatementCacheKey<DB>