Struct ColumnUse 

pub struct ColumnUse {
    pub columns: Vec<u16>,
    pub rowid: bool,
    pub opaque: bool,
    pub functions: Vec<(Vec<u8>, Vec<BoundExpr>)>,
}

Which of one FROM term’s columns a query reads.

Fields

columns: Vec<u16>

The record slots read, ascending and without duplicates.

rowid: bool

Whether the term’s rowid is read.

opaque: bool

Whether something was met whose column reads cannot be enumerated.

An opaque use is never coverable. It is set rather than ignored because the whole value of this answer is that it is complete: a covering path that turned out not to cover a column would read it from an index that does not hold it.

functions: Vec<(Vec<u8>, Vec<BoundExpr>)>

The module’s auxiliary functions this term is asked for, in the order they were met, as a folded name and the arguments after the table.

score(t) and bm25(t) read the cursor rather than a column, so they are neither a column read nor an opaque one: the module can answer them per row, and a materialised virtual scan carries the answers beside the columns. Recorded here because this is already the answer to “what does this term have to produce”, and a second list would be a second thing that can disagree with it. The arguments, not their count. highlight(t, 0, '[', ']') and bm25(t, 10.0, 1.0) are answered by the module from the cursor, and the module cannot answer either without the values - which used to be dropped here and replaced with an empty list at the call, so every auxiliary function saw no arguments at all. Two calls of one name with different arguments are also two different answers, so the arguments are part of what identifies a slot rather than a detail hanging off one.

Implementations

impl ColumnUse

pub fn add(&mut self, slot: u16)

Records that one slot is read.

pub fn add_function(&mut self, name: &[u8], arguments: &[BoundExpr])

Records that one of the module’s auxiliary functions is read.

@param name - the function’s folded name @param arguments - the arguments after the table

pub fn merge(&mut self, other: &ColumnUse)

Folds another use into this one.

Trait Implementations

impl Clone for ColumnUse

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ColumnUse

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

Formats the value using the given formatter.

impl Default for ColumnUse

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for ColumnUse

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for ColumnUse