Trait ResponseCardinalityExt 

pub trait ResponseCardinalityExt<E: EntityKind>: SealedResponseCardinalityExt<E> {
    // Required methods
    fn require_one(&self) -> Result<(), ResponseError>;
    fn require_some(&self) -> Result<(), ResponseError>;
    fn try_row(self) -> Result<Option<Row<E>>, ResponseError>;
    fn row(self) -> Result<Row<E>, ResponseError>;
    fn try_entity(self) -> Result<Option<E>, ResponseError>;
    fn entity(self) -> Result<E, ResponseError>;
    fn require_id(self) -> Result<Id<E>, ResponseError>;
}

ResponseCardinalityExt

Query/session-layer cardinality helpers for scalar EntityResponse<E> payloads. These methods intentionally live outside db::response so cardinality semantics remain owned by the query/session API boundary.

Required Methods

fn require_one(&self) -> Result<(), ResponseError>

Require exactly one row in this response.

fn require_some(&self) -> Result<(), ResponseError>

Require at least one row in this response.

fn try_row(self) -> Result<Option<Row<E>>, ResponseError>

Consume and return None for empty, Some(row) for one row, or error for many rows.

fn row(self) -> Result<Row<E>, ResponseError>

Consume and return the single row, or fail on zero/many rows.

fn try_entity(self) -> Result<Option<E>, ResponseError>

Consume and return the single entity or None, failing on many rows.

fn entity(self) -> Result<E, ResponseError>

Consume and return the single entity, failing on zero/many rows.

fn require_id(self) -> Result<Id<E>, ResponseError>

Require exactly one row and return its identifier.

Implementors

impl<E: EntityKind> ResponseCardinalityExt<E> for EntityResponse<E>