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>; }
Expand description

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 returned on query

Associated Constants

Metadata for the storage kind.

Required methods

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

Convert a query to an optional value.

Implementors