Struct sqlx_core::query::Map

pub struct Map<'q, DB: Database, F, A> { /* private fields */ }

SQL query that will map its results to owned Rust types.

Returned by Query::try_map, query!(), etc. Has most of the same methods as Query but the return types are changed to reflect the mapping. However, there is no equivalent of Query::execute as it doesn’t make sense to map the result type and then ignore it.

Query::bind is also omitted; stylistically we recommend placing your .bind() calls before .try_map(). This is also to prevent adding superfluous binds to the result of query!() et al.

Implementations

impl<'q, DB, F, O, A> Map<'q, DB, F, A> where
    DB: Database,
    F: FnMut(DB::Row) -> Result<O, Error> + Send,
    O: Send + Unpin,
    A: 'q + Send + IntoArguments<'q, DB>, 

pub fn map<G, P>(
    self,
    g: G
) -> Map<'q, DB, impl FnMut(DB::Row) -> Result<P, Error> + Send, A> where
    G: FnMut(O) -> P + Send,
    P: Unpin, 

Map each row in the result to another type.

See try_map for a fallible version of this method.

The query_as method will construct a mapped query using a FromRow implementation.

pub fn try_map<G, P>(
    self,
    g: G
) -> Map<'q, DB, impl FnMut(DB::Row) -> Result<P, Error> + Send, A> where
    G: FnMut(O) -> Result<P, Error> + Send,
    P: Unpin, 

Map each row in the result to another type.

The query_as method will construct a mapped query using a FromRow implementation.

pub fn fetch<'e, 'c: 'e, E>(
    self,
    executor: E
) -> BoxStream<'e, Result<O, Error>> where
    'q: 'e,
    E: 'e + Executor<'c, Database = DB>,
    DB: 'e,
    F: 'e,
    O: 'e, 

Execute the query and return the generated results as a stream.

pub fn fetch_many<'e, 'c: 'e, E>(
    self,
    executor: E
) -> BoxStream<'e, Result<Either<DB::QueryResult, O>, Error>> where
    'q: 'e,
    E: 'e + Executor<'c, Database = DB>,
    DB: 'e,
    F: 'e,
    O: 'e, 

Execute multiple queries and return the generated results as a stream from each query, in a stream.

pub async fn fetch_all<'e, 'c: 'e, E>(
    self,
    executor: E
) -> Result<Vec<O>, Error> where
    'q: 'e,
    E: 'e + Executor<'c, Database = DB>,
    DB: 'e,
    F: 'e,
    O: 'e, 

Execute the query and return all the generated results, collected into a Vec.

pub async fn fetch_one<'e, 'c: 'e, E>(self, executor: E) -> Result<O, Error> where
    'q: 'e,
    E: 'e + Executor<'c, Database = DB>,
    DB: 'e,
    F: 'e,
    O: 'e, 

Execute the query and returns exactly one row.

pub async fn fetch_optional<'e, 'c: 'e, E>(
    self,
    executor: E
) -> Result<Option<O>, Error> where
    'q: 'e,
    E: 'e + Executor<'c, Database = DB>,
    DB: 'e,
    F: 'e,
    O: 'e, 

Execute the query and returns at most one row.

Trait Implementations

impl<'q, DB, F: Send, A: Send> Execute<'q, DB> for Map<'q, DB, F, A> where
    DB: Database,
    A: IntoArguments<'q, DB>, 

fn sql(&self) -> &'q str

Gets the SQL that will be executed.

fn statement(&self) -> Option<&<DB as HasStatement<'q>>::Statement>

Gets the previously cached statement, if available.

fn take_arguments(&mut self) -> Option<<DB as HasArguments<'q>>::Arguments>

Returns the arguments to be bound against the query string.

fn persistent(&self) -> bool

Returns true if the statement should be cached.