Enum LoadingStrategy 

pub enum LoadingStrategy {
    Joined,
    Selectin,
    Subquery,
    Lazy,
    Raise,
    NoLoad,
    WriteOnly,
    Dynamic,
}

Available on native and crate feature proxy and crate feature routing only.

Loading strategy for relationships Corresponds to SQLAlchemy’s lazy parameter and loader options

Variants

Joined

Load immediately with parent via JOIN Most efficient for single objects, can cause cartesian product for collections SQLAlchemy: lazy=‘joined’ or joinedload()

Selectin

Load in a separate SELECT IN query after parent loads Most efficient for collections, avoids cartesian product SQLAlchemy: lazy=‘selectin’ or selectinload()

Subquery

Load via subquery that wraps the parent query SQLAlchemy: lazy=‘subquery’ or subqueryload()

Lazy

Load on first access (traditional lazy loading) SQLAlchemy: lazy=‘select’ or lazy=True

Raise

Raise error if accessed when not loaded Useful to catch N+1 query problems during development SQLAlchemy: lazy=‘raise’ or raiseload()

NoLoad

Never load automatically, must be loaded explicitly SQLAlchemy: lazy=‘noload’ or noload()

WriteOnly

Write-only relationship, cannot be read Useful for large collections that should only be modified SQLAlchemy: lazy=‘write_only’

Dynamic

Return a dynamic query object instead of loading Allows further filtering on the relationship SQLAlchemy: lazy=‘dynamic’

Implementations

impl LoadingStrategy

pub fn is_eager(&self) -> bool

Available on crate feature database only.

Check if this strategy requires immediate loading

pub fn is_lazy(&self) -> bool

Available on crate feature database only.

Check if this strategy loads on access

pub fn prevents_load(&self) -> bool

Available on crate feature database only.

Check if this strategy prevents loading

pub fn sql_hint(&self) -> Option<&'static str>

Available on crate feature database only.

Get SQL hint for query planner

Trait Implementations

impl Clone for LoadingStrategy

fn clone(&self) -> LoadingStrategy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for LoadingStrategy

impl Debug for LoadingStrategy

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

Formats the value using the given formatter.

impl Eq for LoadingStrategy

impl Hash for LoadingStrategy

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for LoadingStrategy

fn eq(&self, other: &LoadingStrategy) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for LoadingStrategy