Enum RelExpr

pub enum RelExpr {
    RelVar(Relvar),
    Select(Box<RelExpr>, Expr),
    LeftDeepJoin(LeftDeepJoin),
    EqJoin(LeftDeepJoin, FieldProject, FieldProject),
}

A logical relational expression

Variants

RelVar(Relvar)

A relvar or table reference

Select(Box<RelExpr>, Expr)

A logical select for filter

LeftDeepJoin(LeftDeepJoin)

A left deep binary cross product

EqJoin(LeftDeepJoin, FieldProject, FieldProject)

A left deep binary equi-join

Implementations

impl RelExpr

pub fn visit(&self, f: &mut impl FnMut(&Self))

Walk the expression tree and call f on each node

pub fn visit_mut(&mut self, f: &mut impl FnMut(&mut Self))

Walk the expression tree and call f on each node

pub fn nfields(&self) -> usize

The number of fields this expression returns

pub fn has_field(&self, field: &str) -> bool

Does this expression return this field?

pub fn find_table_schema(&self, alias: &str) -> Option<&TableSchema>

Return the TableSchema for a relvar in the expression

pub fn find_table_id(&self, alias: &str) -> Option<TableId>

Return the TableId for a relvar in the expression

pub fn return_table(&self) -> Option<&TableSchema>

Does this expression return a single relvar? If so, return it’s TableSchema, otherwise return None.

pub fn return_table_id(&self) -> Option<TableId>

Does this expression return a single relvar? If so, return it’s TableId, otherwise return None.

pub fn return_name(&self) -> Option<&str>

Does this expression return a single relvar? If so, return its name or equivalently its alias.

Trait Implementations

impl Clone for RelExpr

fn clone(&self) -> RelExpr

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RelExpr

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

Formats the value using the given formatter.

impl PartialEq for RelExpr

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for RelExpr

impl StructuralPartialEq for RelExpr