Trait frame_support::storage::types::QueryKindTrait[−][src]

pub trait QueryKindTrait<Value, OnEmpty> {
    type Query: FullCodec + 'static;

    const METADATA: StorageEntryModifier;

    fn from_optional_value_to_query(v: Option<Value>) -> Self::Query;
    fn from_query_to_optional_value(v: Self::Query) -> Option<Value>;
}

Trait implementing how the storage optional value is converted into the queried type.

It is implemented by:

OptionQuery which convert an optional value to an optional value, user when querying storage will get an optional value.
ValueQuery which convert an optional value to a value, user when querying storage will get a value.

Associated Types

`type Query: FullCodec + 'static`[src]

Type returned on query

Loading content...

Associated Constants

`const METADATA: StorageEntryModifier`[src]

Metadata for the storage kind.

Loading content...

Required methods

`fn from_optional_value_to_query(v: Option<Value>) -> Self::Query`[src]

Convert an optional value (i.e. some if trie contains the value or none otherwise) to the query.

`fn from_query_to_optional_value(v: Self::Query) -> Option<Value>`[src]

Convert a query to an optional value.

Loading content...

Implementors

`impl<Value> QueryKindTrait<Value, GetDefault> for OptionQuery where Value: FullCodec + 'static,` [src]

`const METADATA: StorageEntryModifier`[src]

`type Query = Option<Value>`

`fn from_optional_value_to_query(v: Option<Value>) -> Self::Query`[src]

`fn from_query_to_optional_value(v: Self::Query) -> Option<Value>`[src]

`impl<Value, OnEmpty> QueryKindTrait<Value, OnEmpty> for ValueQuery where Value: FullCodec + 'static, OnEmpty: Get<Value>,` [src]

`const METADATA: StorageEntryModifier`[src]

`type Query = Value`

`fn from_optional_value_to_query(v: Option<Value>) -> Self::Query`[src]

`fn from_query_to_optional_value(v: Self::Query) -> Option<Value>`[src]

Loading content...