Struct scylla::transport::query_result::QueryRowsResult

pub struct QueryRowsResult { /* private fields */ }

Enables deserialization of rows received from the database in a QueryResult.

Upon creation, it deserializes result metadata and allocates it.

This struct provides generic methods which enable typed access to the data, by deserializing rows on the fly to the type provided as a type parameter. Those methods are:

• rows() - for iterating through rows,
• first_row() and maybe_first_row() - for accessing the first row,
• single_row() - for accessing the first row, additionally asserting that it’s the only one in the response.

let rows_result = query_result.into_rows_result()?;

let mut rows_iter = rows_result.rows::<(i32, &str)>()?;
while let Some((num, text)) = rows_iter.next().transpose()? {
    // do something with `num` and `text``
}

Ok(())

Implementations

impl QueryRowsResult

pub fn warnings(&self) -> impl Iterator<Item = &str>

Warnings emitted by the database.

pub fn tracing_id(&self) -> Option<Uuid>

Tracing ID associated with this CQL request.

pub fn rows_num(&self) -> usize

Returns the number of received rows.

pub fn rows_bytes_size(&self) -> usize

Returns the size of the serialized rows.

pub fn column_specs(&self) -> ColumnSpecs<'_>

Returns column specifications.

pub fn rows<'frame, R: DeserializeRow<'frame, 'frame>>( &'frame self, ) -> Result<TypedRowIterator<'frame, 'frame, R>, RowsError>

Returns an iterator over the received rows.

Returns an error if the rows in the response are of incorrect type.

pub fn maybe_first_row<'frame, R: DeserializeRow<'frame, 'frame>>( &'frame self, ) -> Result<Option<R>, MaybeFirstRowError>

Returns Option<R> containing the first row of the result.

Fails when the the rows in the response are of incorrect type, or when the deserialization fails.

pub fn first_row<'frame, R: DeserializeRow<'frame, 'frame>>( &'frame self, ) -> Result<R, FirstRowError>

Returns the first row of the received result.

When the first row is not available, returns an error. Fails when the the rows in the response are of incorrect type, or when the deserialization fails.

pub fn single_row<'frame, R: DeserializeRow<'frame, 'frame>>( &'frame self, ) -> Result<R, SingleRowError>

Returns the only received row.

Fails if the result is anything else than a single row. Fails when the the rows in the response are of incorrect type, or when the deserialization fails.

Trait Implementations

impl Debug for QueryRowsResult

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

Formats the value using the given formatter.