Struct Only

pub struct Only<S> { /* private fields */ }

Available on crate feature postgres_backend only.

Represents a query with an ONLY clause.

Trait Implementations

impl<S> AsQuery for Only<S>

where S: Table + Clone, <S as QuerySource>::DefaultSelection: ValidGrouping<()> + SelectableExpression<Only<S>>,

type SqlType = <<Only<S> as QuerySource>::DefaultSelection as Expression>::SqlType

The SQL type of Self::Query

type Query = SelectStatement<FromClause<Only<S>>>

What kind of query does this type represent?

fn as_query(self) -> Self::Query

Converts a type which semantically represents a SQL query into the actual query being executed. See the trait level docs for more.

impl<S: Clone> Clone for Only<S>

fn clone(&self) -> Only<S>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<S: Debug> Debug for Only<S>

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

Formats the value using the given formatter.

impl<S: Default> Default for Only<S>

fn default() -> Only<S>

Returns the “default value” for a type.

impl<S> QueryFragment<Pg> for Only<S>

where S: QueryFragment<Pg>,

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

Walk over this QueryFragment for all passes.

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

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

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<()>

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

Serializes all bind parameters in this query.

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

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

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

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

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

Does walking this AST have any effect?

impl<S> QueryId for Only<S>

where Self: 'static, S: QueryId,

const HAS_STATIC_QUERY_ID: bool = <S as QueryId>::HAS_STATIC_QUERY_ID

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

type QueryId = Only<S>

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<S> QuerySource for Only<S>

where S: Table + Clone, <S as QuerySource>::DefaultSelection: ValidGrouping<()> + SelectableExpression<Only<S>>,

type FromClause = Only<S>

The type returned by from_clause

type DefaultSelection = <S as QuerySource>::DefaultSelection

The type returned by default_selection

fn from_clause(&self) -> Self::FromClause

The actual FROM clause of this type. This is typically only called in QueryFragment implementations.

fn default_selection(&self) -> Self::DefaultSelection

The default select clause of this type, which should be used if no select clause was explicitly specified. This should always be a tuple of all the desired columns, not star

impl<S> Table for Only<S>

where S: Table + Clone + AsQuery, <S as Table>::PrimaryKey: SelectableExpression<Only<S>>, <S as Table>::AllColumns: SelectableExpression<Only<S>>, <S as QuerySource>::DefaultSelection: ValidGrouping<()> + SelectableExpression<Only<S>>,

type PrimaryKey = <S as Table>::PrimaryKey

The type returned by primary_key

type AllColumns = <S as Table>::AllColumns

The type returned by all_columns

fn primary_key(&self) -> Self::PrimaryKey

Returns the primary key of this table.

fn all_columns() -> Self::AllColumns

Returns a tuple of all columns belonging to this table.

impl<S: Copy> Copy for Only<S>

impl<S, T> JoinTo<T> for Only<S>

where S: JoinTo<T> + Table, T: Table,