Struct sqlx_core::query::Map

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

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.

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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>,

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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.

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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.

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

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

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

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

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

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

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

Execute the query and returns exactly one row.

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

Execute the query and returns at most one row.

Trait Implementations§

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

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

Gets the SQL that will be executed.
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fn statement(&self) -> Option<&<DB as HasStatement<'q>>::Statement>

Gets the previously cached statement, if available.
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fn take_arguments(&mut self) -> Option<<DB as HasArguments<'q>>::Arguments>

Returns the arguments to be bound against the query string. Read more
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fn persistent(&self) -> bool

Returns true if the statement should be cached.

Auto Trait Implementations§

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impl<'q, DB, F, A> RefUnwindSafe for Map<'q, DB, F, A>

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

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impl<'q, DB, F, A> Sync for Map<'q, DB, F, A>
where A: Sync, DB: Sync, F: Sync,

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impl<'q, DB, F, A> Unpin for Map<'q, DB, F, A>
where A: Unpin, DB: Unpin, F: Unpin,

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impl<'q, DB, F, A> UnwindSafe for Map<'q, DB, F, A>

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V