Struct Many

pub struct Many<ST, I> {
    pub values: Vec<I>,
    /* private fields */
}

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

Query dsl node for the values part of an IN (values) clause containing a variable number of bind values.

Third party backend can customize the QueryFragment implementation of this query dsl node via SqlDialect::ArrayComparison. The default implementation does generate one bind per value in the values field.

Diesel provides an optimized implementation for Postgresql like database systems that bind all values with one bind value of the type Array<ST> instead.

Fields

values: Vec<I>

The values contained in the IN (values) clause

Trait Implementations

impl<ST: Clone, I: Clone> Clone for Many<ST, I>

fn clone(&self) -> Many<ST, I>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<ST: Debug, I: Debug> Debug for Many<ST, I>

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

Formats the value using the given formatter.

impl<ST, I> Expression for Many<ST, I>

where ST: TypedExpressionType,

type SqlType = NotSelectable

The type that this expression represents in SQL

impl<ST, I> InExpression for Many<ST, I>

where ST: SqlType,

type SqlType = ST

The SQL type of the inner values, which should be the same as the left of the IN or NOT IN clause

fn is_empty(&self) -> bool

Returns true if self represents an empty collection Otherwise false is returned.

fn is_array(&self) -> bool

Returns true if the values clause represents bind values and each bind value is a postgres array type

impl<ST, I, DB> QueryFragment<DB> for Many<ST, I>

where Self: QueryFragment<DB, DB::ArrayComparison>, DB: Backend,

fn walk_ast<'b>(&'b self, pass: AstPass<'_, 'b, DB>) -> QueryResult<()>

Walk over this QueryFragment for all passes.

fn to_sql(&self, out: &mut DB::QueryBuilder, backend: &DB) -> QueryResult<()>

Converts this QueryFragment to its SQL representation.

fn collect_binds<'b>( &'b self, out: &mut DB::BindCollector<'b>, metadata_lookup: &mut DB::MetadataLookup, backend: &'b DB, ) -> QueryResult<()>

Serializes all bind parameters in this query.

fn is_safe_to_cache_prepared(&self, backend: &DB) -> QueryResult<bool>

Is this query safe to store in the prepared statement cache?

fn is_noop(&self, backend: &DB) -> QueryResult<bool>

Does walking this AST have any effect?

impl<ST, I, DB> QueryFragment<DB, AnsiSqlArrayComparison> for Many<ST, I>

where DB: Backend + HasSqlType<ST> + SqlDialect<ArrayComparison = AnsiSqlArrayComparison>, ST: SingleValue, I: ToSql<ST, DB>,

fn walk_ast<'b>(&'b self, out: AstPass<'_, 'b, DB>) -> QueryResult<()>

Walk over this QueryFragment for all passes.

fn to_sql(&self, out: &mut DB::QueryBuilder, backend: &DB) -> QueryResult<()>

Converts this QueryFragment to its SQL representation.

fn collect_binds<'b>( &'b self, out: &mut DB::BindCollector<'b>, metadata_lookup: &mut DB::MetadataLookup, backend: &'b DB, ) -> QueryResult<()>

Serializes all bind parameters in this query.

fn is_safe_to_cache_prepared(&self, backend: &DB) -> QueryResult<bool>

Is this query safe to store in the prepared statement cache?

fn is_noop(&self, backend: &DB) -> QueryResult<bool>

Does walking this AST have any effect?

impl<ST, I> QueryId for Many<ST, I>

const HAS_STATIC_QUERY_ID: bool = false

Can the SQL generated by Self be uniquely identified by its type?

type QueryId = ()

A type which uniquely represents Self in a SQL query.

fn query_id() -> Option<TypeId>

Returns the type id of Self::QueryId if Self::HAS_STATIC_QUERY_ID. Returns None otherwise.

impl<ST, I, GB> ValidGrouping<GB> for Many<ST, I>

where ST: SingleValue, I: AsExpression<ST>, I::Expression: ValidGrouping<GB>,

type IsAggregate = <<I as AsExpression<ST>>::Expression as ValidGrouping<GB>>::IsAggregate

Is this expression aggregate?

impl<ST, I, QS> AppearsOnTable<QS> for Many<ST, I>

where Many<ST, I>: Expression, I: AsExpression<ST>, ST: SingleValue, <I as AsExpression<ST>>::Expression: SelectableExpression<QS>,

impl<ST, I, QS> SelectableExpression<QS> for Many<ST, I>

where Many<ST, I>: AppearsOnTable<QS>, ST: SingleValue, I: AsExpression<ST>, <I as AsExpression<ST>>::Expression: SelectableExpression<QS>,