Struct QueryPlan 

pub struct QueryPlan {

    pub source: QuerySource,
    pub projection: Vec<SelectExpr>,
    pub joins: Vec<JoinExpr>,
    pub filter: Option<Expr>,
    pub grouping: Vec<Expr>,
    pub having: Option<Expr>,
    pub ordering: Vec<OrderExpr>,
    pub limit: Option<u64>,
    pub offset: Option<u64>,
    pub distinct: DistinctMode,
    pub lock: Option<LockMode>,
    pub compound: Vec<Compound>,
    pub origin: Option<PlanOrigin>,
}

Backend-neutral read query.

Built immutably: every builder method consumes and returns self, so a QuerySet can clone a base plan and branch safely.

Fields

source: QuerySource

Root source.

projection: Vec<SelectExpr>

Projection; empty means “all columns of the root source”.

joins: Vec<JoinExpr>

Joins.

filter: Option<Expr>

WHERE.

grouping: Vec<Expr>

GROUP BY.

having: Option<Expr>

HAVING.

ordering: Vec<OrderExpr>

ORDER BY.

limit: Option<u64>

LIMIT.

offset: Option<u64>

OFFSET.

distinct: DistinctMode

Distinct mode.

lock: Option<LockMode>

Row lock.

compound: Vec<Compound>

Queries combined with this one (UNION …). ordering, limit and offset of this plan then apply to the combined result, and every member must project the same number of columns.

origin: Option<PlanOrigin>

Database the plan was built against, recorded when a QuerySet becomes a subquery. Never compiled; Db uses it to reject a subquery that belongs to another database.

Implementations

impl QueryPlan

pub fn from_table(table: impl Into<Ident>) -> Self

Plan selecting every row of table.

pub fn from_subquery(inner: QueryPlan, alias: impl Into<Ident>) -> Self

Plan selecting every row of the derived table (inner) AS alias.

pub fn select(self, expr: impl Into<Expr>, alias: Option<&'static str>) -> Self

Add a projected expression.

pub fn filter(self, predicate: Expr) -> Self

AND a predicate into the filter.

pub fn exclude(self, predicate: Expr) -> Self

AND the negation of a predicate into the filter (Django exclude).

pub fn order_by(self, expr: impl Into<Expr>, direction: OrderDirection) -> Self

Append an ordering term.

pub fn limit(self, n: u64) -> Self

Set LIMIT.

pub fn offset(self, n: u64) -> Self

Set OFFSET.

pub fn join(self, kind: JoinKind, source: QuerySource, on: Expr) -> Self

Add a join.

pub fn lock(self, mode: LockMode) -> Self

Request a row lock.

pub fn distinct(self, mode: DistinctMode) -> Self

Set distinct mode.

pub fn required_features(&self) -> Vec<Feature>

Features this plan needs from a backend (deduplicated).

pub fn resolve_relations(self) -> Self

Replace Expr::Related columns by joined-table columns, adding the needed LEFT JOINs (deduplicated by alias) to this plan and to nested plans. Idempotent; querysets call it after every builder step.

pub fn has_foreign_origin(&self, origin: PlanOrigin) -> bool

Whether this plan, or any plan nested in it, was built against a database other than origin.

pub fn check( &self, caps: &BackendCapabilities, ) -> Result<(), BackendCapabilityError>

Check the plan against backend capabilities.

Trait Implementations

impl Clone for QueryPlan

fn clone(&self) -> QueryPlan

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for QueryPlan

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

Formats the value using the given formatter.

impl PartialEq for QueryPlan

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for QueryPlan