Trait diesel::query_builder::QueryFragment

pub trait QueryFragment<DB: Backend, SP = NotSpecialized> {
    fn walk_ast<'b>(&'b self, pass: AstPass<'_, 'b, DB>) -> QueryResult<()>;
}

An untyped fragment of SQL.

This may be a complete SQL command (such as an update statement without a RETURNING clause), or a subsection (such as our internal types used to represent a WHERE clause). Implementations of ExecuteDsl and LoadQuery will generally require that this trait be implemented.

Required Methods

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

Walk over this QueryFragment for all passes.

This method is where the actual behavior of an AST node is implemented. This method will contain the behavior required for all possible AST passes. See AstPass for more details.

Trait Implementations

impl<DB> QueryId for dyn QueryFragment<DB>

type QueryId = ()

A type which uniquely represents Self in a SQL query.

const HAS_STATIC_QUERY_ID: bool = false

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

fn query_id() -> Option<TypeId>

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

Implementors