Enum Columns 

pub enum Columns {
    Fixed(Vec<Field>),
    Parquet,
    Csv,
}

Where a call’s columns come from.

A table function that produces a fixed set of columns is resolved by this crate and nothing else has to be consulted. One that reads a file is not, because the columns are in the file, so the answer here is which file to open rather than what is in it. An enum rather than an empty column list, because an empty list is what read_parquet of a file with no columns would also give and a caller that forgot to handle the case would get an empty table instead of an error.

Variants

Fixed(Vec<Field>)

The columns this call produces, with the names an unaliased call gives them.

Parquet

The columns of the Parquet file the first argument names.

Csv

The columns of the CSV file the first argument names, which are sniffed out of its front.

Trait Implementations

impl Clone for Columns

fn clone(&self) -> Columns

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Columns

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

Formats the value using the given formatter.

impl Eq for Columns

impl PartialEq for Columns

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Columns