Struct SqliteBindCollectorData 

#[non_exhaustive]
pub struct SqliteBindCollectorData { /* private fields */ }

Available on crate features __sqlite-shared and i-implement-a-third-party-backend-and-opt-into-breaking-changes only.

SQLite bind collector data that is movable across threads.

This is the Send snapshot produced by MoveableBindCollector::moveable on a SqliteBindCollector. Both borrowed and owned string or blob variants of SqliteBindValueRef collapse into their OwnedSqliteBindValue counterparts, so a caller crossing a thread boundary carries no borrows from the original query. For a zero-copy view of the live collector see SqliteBindCollector::binds.

Implementations

impl SqliteBindCollectorData

pub fn binds( &self, ) -> impl ExactSizeIterator<Item = (&OwnedSqliteBindValue, SqliteType)>

Iterate over the collected bind values and their SQLite storage classes, in positional order.

The values yielded are the moved OwnedSqliteBindValue snapshot, so this method is safe to call from any thread. For a zero-copy view of the live collector see SqliteBindCollector::binds.

Example

A third-party backend can snapshot the ordered bind values of a typed Diesel query and inspect the owned variants:

use diesel::expression::IntoSql;
use diesel::query_builder::{MoveableBindCollector, QueryFragment};
use diesel::sql_types::{Binary, Integer, Nullable, Text};
use diesel::sqlite::{
    OwnedSqliteBindValue, Sqlite, SqliteBindCollector, SqliteBindCollectorData, SqliteType,
};

fn snapshot<Q: QueryFragment<Sqlite>>(query: &Q) -> SqliteBindCollectorData {
    let mut collector = SqliteBindCollector::new();
    query.collect_binds(&mut collector, &mut (), &Sqlite).unwrap();
    collector.moveable()
}

let query = diesel::select((
    42_i32.into_sql::<Integer>(),
    "hi".into_sql::<Text>(),
    vec![1_u8, 2, 3].into_sql::<Binary>(),
    None::<i32>.into_sql::<Nullable<Integer>>(),
));

let data = snapshot(&query);

// Types survive the move.
let types: Vec<_> = data.binds().map(|(_, t)| t).collect();
assert_eq!(
    types,
    [SqliteType::Integer, SqliteType::Text, SqliteType::Binary, SqliteType::Integer],
);

// Borrowed variants normalize into their owned counterparts.
let binds: Vec<_> = data.binds().collect();
assert!(matches!(binds[0].0, OwnedSqliteBindValue::I32(42)));
assert!(matches!(binds[1].0, OwnedSqliteBindValue::String(s) if &**s == "hi"));
assert!(matches!(binds[2].0, OwnedSqliteBindValue::Binary(b) if **b == [1, 2, 3]));
assert!(matches!(binds[3].0, OwnedSqliteBindValue::Null));

Trait Implementations

impl Debug for SqliteBindCollectorData

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

Formats the value using the given formatter.