Struct SqlProjectionHint 

#[non_exhaustive]
pub struct SqlProjectionHint {
    pub database: DatabaseType,
    pub projection_template: String,
    pub estimated_reduction_percent: u32,
}

SQL projection hint for database-specific field projection optimization.

When a type has a large JSONB payload, the compiler can generate SQL that projects only the requested fields, reducing network payload and JSON deserialization overhead.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

database: DatabaseType

Database type — typed to prevent silent typos (e.g. "postgresq") that would cause adapters to silently ignore the hint.

projection_template: String

The projection SQL template. Example for PostgreSQL: jsonb_build_object('id', data->>'id', 'email', data->>'email')

estimated_reduction_percent: u32

Estimated reduction in payload size (percentage 0-100).

Implementations

impl SqlProjectionHint

pub const fn new( database: DatabaseType, projection_template: String, estimated_reduction_percent: u32, ) -> Self

Creates a new SqlProjectionHint.

Trait Implementations

impl Clone for SqlProjectionHint

fn clone(&self) -> SqlProjectionHint

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SqlProjectionHint

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for SqlProjectionHint

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for SqlProjectionHint

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for SqlProjectionHint

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for SqlProjectionHint

impl StructuralPartialEq for SqlProjectionHint