Struct AsyncPreparedStatement 

pub struct AsyncPreparedStatement<'conn> { /* private fields */ }

A handle to a server-side prepared statement (async).

Construct via AsyncConnection::prepare or AsyncConnection::prepare_typed. Holding this type keeps the statement allocated on the server; it is released automatically when the handle is dropped (best-effort — see hyperdb_api_core::client::AsyncPreparedStatement for the Drop semantics). The owned variant AsyncPreparedStatementOwned also provides an explicit close method for callers that want deterministic cleanup.

Implementations

impl<'conn> AsyncPreparedStatement<'conn>

pub fn param_count(&self) -> usize

Number of parameters the statement expects.

pub fn param_types(&self) -> &[Oid]

Parameter type OIDs.

pub fn schema(&self) -> &ResultSchema

Result-column schema, always available (captured at prepare time).

pub fn sql(&self) -> &str

The original SQL text.

pub async fn query( &self, params: &[&dyn ToSqlParam], ) -> Result<AsyncRowset<'conn>>

Executes the statement and returns a streaming AsyncRowset.

Errors

• Returns Error::Other on gRPC transport.
• Returns Error::Client if the server rejects Bind or Execute.
• Returns Error::Io on transport-level I/O failures.

pub async fn execute(&self, params: &[&dyn ToSqlParam]) -> Result<u64>

Executes the statement as a command and returns the affected-row count (async).

Errors

• Returns Error::Other on gRPC transport.
• Returns Error::Client if the server rejects Bind or Execute.
• Returns Error::Io on transport-level I/O failures.

pub async fn fetch_one(&self, params: &[&dyn ToSqlParam]) -> Result<Row>

Fetches exactly one row; errors if the result is empty.

Errors

• Returns the error from query.
• Returns Error::Other with message "Query returned no rows" if the result is empty.

pub async fn fetch_optional( &self, params: &[&dyn ToSqlParam], ) -> Result<Option<Row>>

Fetches at most one row; returns None if the result is empty.

Errors

Returns the error from query; an empty result yields Ok(None).

pub async fn fetch_all(&self, params: &[&dyn ToSqlParam]) -> Result<Vec<Row>>

Fetches every row into a Vec.

Errors

Returns the error from query, or a transport error produced while draining every chunk.

pub async fn fetch_scalar<T: RowValue>( &self, params: &[&dyn ToSqlParam], ) -> Result<T>

Fetches a single non-NULL scalar; errors on empty / NULL.

Errors

• Returns the error from query.
• Returns Error::Other with message "Query returned no rows" if the result is empty.
• Returns Error::Other with message "Scalar query returned NULL" if the first cell is SQL NULL.

pub async fn fetch_optional_scalar<T: RowValue>( &self, params: &[&dyn ToSqlParam], ) -> Result<Option<T>>

Fetches a single scalar, allowing NULL as None.

Errors

Returns the error from query; SQL NULL yields Ok(None).

Trait Implementations

impl<'conn> Debug for AsyncPreparedStatement<'conn>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.