Trait diesel::expression::QueryMetadata
source · pub trait QueryMetadata<T>: Backend {
fn row_metadata(
lookup: &mut Self::MetadataLookup,
out: &mut Vec<Option<Self::TypeMetadata>>
);
}Expand description
A helper to translate type level sql type information into runtime type information for specific queries
If you do not implement a custom backend implementation this trait is likely not relevant for you.
Required Methods§
sourcefn row_metadata(
lookup: &mut Self::MetadataLookup,
out: &mut Vec<Option<Self::TypeMetadata>>
)
fn row_metadata(
lookup: &mut Self::MetadataLookup,
out: &mut Vec<Option<Self::TypeMetadata>>
)
The exact return value of this function is considerded to be a backend specific implementation detail. You should not rely on those values if you not own the corresponding backend