Struct Query

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

Raw SQL query with bind parameters. Returned by query.

Implementations

impl<'q, DB> Query<'q, DB, <DB as HasArguments<'q>>::Arguments>

where DB: Database,

pub fn bind<T>( self, value: T, ) -> Query<'q, DB, <DB as HasArguments<'q>>::Arguments>

where T: 'q + Send + Encode<'q, DB> + Type<DB>,

Bind a value for use with this SQL query.

If the number of times this is called does not match the number of bind parameters that appear in the query (? for most SQL flavors, $1 .. $N for Postgres) then an error will be returned when this query is executed.

There is no validation that the value is of the type expected by the query. Most SQL flavors will perform type coercion (Postgres will return a database error).

impl<'q, DB, A> Query<'q, DB, A>

where DB: Database + HasStatementCache,

pub fn persistent(self, value: bool) -> Query<'q, DB, A>

If true, the statement will get prepared once and cached to the connection’s statement cache.

If queried once with the flag set to true, all subsequent queries matching the one with the flag will use the cached statement until the cache is cleared.

Default: true.

impl<'q, DB, A> Query<'q, DB, A>

where A: Send + 'q + IntoArguments<'q, DB>, DB: Database,

pub fn map<F, O>( self, f: F, ) -> Map<'q, DB, impl FnMut(<DB as Database>::Row) + Send, A>

where F: FnMut(<DB as Database>::Row) -> O + Send, O: 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<F, O>(self, f: F) -> Map<'q, DB, F, A>

where F: FnMut(<DB as Database>::Row) -> Result<O, Error> + Send, O: Unpin,

Map each row in the result to another type.

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

pub async fn execute<'e, 'c, E>( self, executor: E, ) -> Result<<DB as Database>::QueryResult, Error>

where 'c: 'e, 'q: 'e, A: 'e, E: Executor<'c, Database = DB>,

Execute the query and return the total number of rows affected.

pub async fn execute_many<'e, 'c, E>( self, executor: E, ) -> Pin<Box<dyn Stream<Item = Result<<DB as Database>::QueryResult, Error>> + Send + 'e>>

where 'c: 'e, 'q: 'e, A: 'e, E: Executor<'c, Database = DB>,

Execute multiple queries and return the rows affected from each query, in a stream.

pub fn fetch<'e, 'c, E>( self, executor: E, ) -> Pin<Box<dyn Stream<Item = Result<<DB as Database>::Row, Error>> + Send + 'e>>

where 'c: 'e, 'q: 'e, A: 'e, E: Executor<'c, Database = DB>,

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

pub fn fetch_many<'e, 'c, E>( self, executor: E, ) -> Pin<Box<dyn Stream<Item = Result<Either<<DB as Database>::QueryResult, <DB as Database>::Row>, Error>> + Send + 'e>>

where 'c: 'e, 'q: 'e, A: 'e, E: Executor<'c, Database = DB>,

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>( self, executor: E, ) -> Result<Vec<<DB as Database>::Row>, Error>

where 'c: 'e, 'q: 'e, A: 'e, E: Executor<'c, Database = DB>,

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

pub async fn fetch_one<'e, 'c, E>( self, executor: E, ) -> Result<<DB as Database>::Row, Error>

where 'c: 'e, 'q: 'e, A: 'e, E: Executor<'c, Database = DB>,

Execute the query and returns exactly one row.

pub async fn fetch_optional<'e, 'c, E>( self, executor: E, ) -> Result<Option<<DB as Database>::Row>, Error>

where 'c: 'e, 'q: 'e, A: 'e, E: Executor<'c, Database = DB>,

Execute the query and returns at most one row.

Trait Implementations

impl<'q, DB, A> Execute<'q, DB> for Query<'q, DB, A>

where DB: Database, A: Send + 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.