Enum ProjectList

pub enum ProjectList {
    Name(ProjectName),
    List(RelExpr, Vec<(Box<str>, FieldProject)>),
    Limit(Box<ProjectList>, u64),
    Agg(RelExpr, AggType, Box<str>, AlgebraicType),
}

A projection is the root of any relational expression. This type represents a projection that returns fields.

For example:

select a, b from t

and

select t.a as x from t join s ...

Variants

Name(ProjectName)

List(RelExpr, Vec<(Box<str>, FieldProject)>)

Limit(Box<ProjectList>, u64)

Agg(RelExpr, AggType, Box<str>, AlgebraicType)

Implementations

impl ProjectList

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

Does this expression project a single relvar? If so, we return it’s TableSchema. If not, it projects a list of columns, so we return None.

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

Does this expression project a single relvar? If so, we return it’s TableId. If not, it projects a list of columns, so we return None.

pub fn for_each_return_field(&self, f: impl FnMut(&str, &AlgebraicType))

Iterate over the projected column names and types

Trait Implementations

impl Debug for ProjectList

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

Formats the value using the given formatter.