Trait ExpressionSchema 

pub trait ExpressionSchema: ScalarTypeSchema {
    // Required method
    fn column_reference(
        &self,
        name: &str,
        qualifier: Option<&str>,
    ) -> Result<ColumnReference<'_>, SQLError>;

    // Provided method
    fn whole_row_reference(
        &self,
        qualifier: &str,
    ) -> Result<ColumnReference<'_>, SQLError> { ... }
}

Stored expression encoding needs the original attribute identity and collation as well as its type. Borrow declarations directly when those identities are available; an execution-only schema retains its existing positional contract.

Required Methods

fn column_reference( &self, name: &str, qualifier: Option<&str>, ) -> Result<ColumnReference<'_>, SQLError>

Provided Methods

fn whole_row_reference( &self, qualifier: &str, ) -> Result<ColumnReference<'_>, SQLError>

Whole-row Vars retain attribute zero and the relation’s actual named type, independently of its current live attribute list.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl ExpressionSchema for ColumnTypeSchema<'_>

impl ExpressionSchema for RowSchema