Struct sql::query_model::Model

pub struct Model {
    pub(crate) top_box: BoxId,
    boxes: HashMap<BoxId, Box<RefCell<QueryBox>>>,
    box_id_gen: Gen<BoxId>,
    quantifiers: HashMap<QuantifierId, Box<RefCell<Quantifier>>>,
    quantifier_id_gen: Gen<QuantifierId>,
}

A Query Graph Model instance represents a SQL query. See the design doc for details.

In this representation, SQL queries are represented as a graph of operators, represented as boxes, that are connected via quantifiers. A top-level box represents the entry point of the query.

Each non-leaf box has a set of quantifiers, which are the inputs of the operation it represents. The quantifier adds information about how the relation represented by its input box is consumed by the parent box.

Fields

top_box: BoxId

The ID of the box representing the entry-point of the query.

boxes: HashMap<BoxId, Box<RefCell<QueryBox>>>

All boxes in the query graph model.

box_id_gen: Gen<BoxId>

Used for assigning unique IDs to query boxes.

quantifiers: HashMap<QuantifierId, Box<RefCell<Quantifier>>>

All quantifiers in the query graph model.

quantifier_id_gen: Gen<QuantifierId>

Used for assigning unique IDs to quantifiers.

Implementations

impl Model

pub fn as_dot(&self, label: &str) -> Result<String, Error>

impl Model

pub(crate) fn new() -> Self

pub(crate) fn make_box(&mut self, box_type: BoxType) -> BoxId

pub(crate) fn make_select_box(&mut self) -> BoxId

pub(crate) fn boxes_iter(&self) -> impl Iterator<Item = BoundRef<'_, QueryBox>>

An iterator over immutable references to the QueryBox instances in this Model.

pub(crate) fn get_box(&self, box_id: BoxId) -> BoundRef<'_, QueryBox>

Get an immutable reference to the box identified by box_id bound to this Model.

pub(crate) fn get_mut_box(&mut self, box_id: BoxId) -> BoundRefMut<'_, QueryBox>

Get a mutable reference to the box identified by box_id bound to this Model.

pub(crate) fn make_quantifier(
    &mut self,
    quantifier_type: QuantifierType,
    input_box: BoxId,
    parent_box: BoxId
) -> QuantifierId

Create a new quantifier and adds it to the parent box

pub(crate) fn get_quantifier(
    &self,
    quantifier_id: QuantifierId
) -> BoundRef<'_, Quantifier>

Get an immutable reference to the box identified by box_id bound to this Model.

pub(crate) fn get_mut_quantifier(
    &mut self,
    quantifier_id: QuantifierId
) -> BoundRefMut<'_, Quantifier>

Get a mutable reference to the box identified by box_id bound to this Model.

pub(crate) fn try_visit_pre_post<'a, F, G, E>(
    &'a self,
    pre: &mut F,
    post: &mut G
) -> Result<(), E> where
    F: FnMut(&Model, &BoxId) -> Result<(), E>,
    G: FnMut(&Model, &BoxId) -> Result<(), E>, 

Traverse the entire graph using depth-first traversal.

The function pre runs on a parent QueryBox before it runs on any of its children. The function post runs on all children QueryBoxes before it runs on a parent.

pub(crate) fn try_visit_pre_post_descendants<'a, F, G, E>(
    &'a self,
    pre: &mut F,
    post: &mut G,
    root: BoxId
) -> Result<(), E> where
    F: FnMut(&Model, &BoxId) -> Result<(), E>,
    G: FnMut(&Model, &BoxId) -> Result<(), E>, 

Traverse a subgraph using depth-first traversal starting at root.

The function pre runs on a parent QueryBox before it runs on any of its children. The function post runs on all children QueryBoxes before it runs on a parent.

pub(crate) fn try_visit_mut_pre_post<'a, F, G, E>(
    &'a mut self,
    pre: &mut F,
    post: &mut G
) -> Result<(), E> where
    F: FnMut(&mut Model, &BoxId) -> Result<(), E>,
    G: FnMut(&mut Model, &BoxId) -> Result<(), E>, 

Same as Model::try_visit_pre_post, but permits mutating the model.

pub(crate) fn try_visit_mut_pre_post_descendants<'a, F, G, E>(
    &'a mut self,
    pre: &mut F,
    post: &mut G,
    root: BoxId
) -> Result<(), E> where
    F: FnMut(&mut Model, &BoxId) -> Result<(), E>,
    G: FnMut(&mut Model, &BoxId) -> Result<(), E>, 

Same as Model::try_visit_pre_post_descendants, but permits mutating the model.

pub(crate) fn garbage_collect(&mut self)

Removes unreferenced objects from the model.

May be invoked several times during query rewrites.

pub(crate) fn update_ids(&mut self)

Renumbers all the boxes and quantifiers in the model starting from 0.

Intended to be called after Model::garbage_collect.

Renumbering the model does not save memory or improve the performance of traversing the model, but it does make the Dot graph easier to parse.

impl Model

pub fn optimize(&mut self)

impl Model

pub fn validate(&self) -> ValidationResult

Validate a model with a default validator chain.

Trait Implementations

impl Debug for Model

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

Formats the value using the given formatter.

impl From<HirRelationExpr> for Model

fn from(expr: HirRelationExpr) -> Model

Performs the conversion.

impl From<Model> for MirRelationExpr

fn from(model: Model) -> MirRelationExpr

Performs the conversion.