Struct mz_sql::query_model::hir::qgm_from_hir::FromHir

struct FromHir {
    model: Model,
    context_stack: Vec<BoxId>,
    gets_seen: HashMap<Id, BoxId>,
}

Fields

model: Model

context_stack: Vec<BoxId>

The stack of context boxes for resolving offset-based column references.

gets_seen: HashMap<Id, BoxId>

Track the BoxId that represents each HirRelationExpr::Get expression we have seen so far.

Implementations

impl FromHir

fn generate(self, expr: HirRelationExpr) -> Result<Model, QGMError>

Generates a Query Graph Model for representing the given query.

fn generate_select(&mut self, expr: HirRelationExpr) -> Result<BoxId, QGMError>

Generates a sub-graph representing the given expression, ensuring that the resulting graph starts with a Select box.

fn generate_internal(&mut self, expr: HirRelationExpr) -> Result<BoxId, QGMError>

Generates a sub-graph representing the given expression.

fn wrap_within_select(&mut self, box_id: BoxId) -> BoxId

Returns a Select box ranging over the given box, projecting all of its columns.

fn generate_expr(
    &mut self,
    expr: HirScalarExpr,
    context_box: BoxId
) -> Result<BoxScalarExpr, QGMError>

Lowers the given expression within the context of the given box.

Note that this method may add new quantifiers to the box for subquery expressions.

fn generate_exprs(
    &mut self,
    exprs: Vec<HirScalarExpr>,
    context_box: BoxId
) -> Result<Vec<BoxScalarExpr>, QGMError>

Lowers the given expressions within the context of the given box.

Delegates to FromHir::generate_expr for each element.

fn find_column_within_box(
    &self,
    box_id: BoxId,
    position: usize
) -> ColumnReference

Find the N-th column among the columns projected by the input quantifiers of the given box. This method translates Hir’s offset-based column into quantifier-based column references.

This method is equivalent to expr::JoinInputMapper::map_column_to_local, in the sense that given all the columns projected by a join (represented by the set of input quantifiers of the given box) it returns the input the column belongs to and its offset within the projection of the underlying operator.

fn within_context<F, T>(&mut self, context_box: BoxId, f: &mut F) -> Twhere
    F: FnMut(&mut Self) -> T,

Executes the given action within the context of the given box.

fn add_predicate(&mut self, box_id: BoxId, predicate: BoxScalarExpr)

Adds the given predicate to the given box.

The given box must support predicates, ie. it must be either a Select box or an OuterJoin one.

Trait Implementations

impl Default for FromHir

fn default() -> FromHir

Returns the “default value” for a type.