Enum ColumnScope 

pub enum ColumnScope<'a> {
    Unchecked,
    Relations(&'a TableScope),
}

The relations an identifier in this expression can name.

Variants

Unchecked

No relation is in scope, so no identifier is checkable here.

Used where an expression has no FROM clause behind it: stored DEFAULT expressions, partial-index predicates, and the constant folders. A column reference reaching one of those fails in constant folding as SqlError::Unsupported, which is the correct answer there — the value is not row-dependent.

Relations(&'a TableScope)

Identifiers resolve against these relations. One that resolves against no relation, output alias, or synthetic column raises SqlError::UnknownColumn.

Implementations

impl ColumnScope<'_>

pub fn check_column(&self, table_ref: Option<&str>, column: &str) -> Result<()>

Reject column, optionally qualified by table_ref, when it names nothing in this scope.

pub fn column_qualifier( &self, table_ref: Option<&str>, column: &str, ) -> Result<Option<String>>

Check column, optionally qualified by table_ref, and return the qualifier its converted reference carries.

Outside a join’s input clauses the qualifier is kept as written. In them, an unqualified column gets its owning relation’s qualifier, so it reads the qualifier.column key of the merged row.

pub fn is_row_scope(&self) -> bool

Whether an expression here is evaluated once per row of some relation.

Unchecked stands behind stored DEFAULTs, index predicates, and the constant folders, none of which iterate rows.

pub fn allows_cp_functions(&self) -> bool

Whether a sequence accessor resolves here although rows are in scope.

Only a SELECT-list scope over a relation says yes; the Control Plane evaluates that item per output row. Unchecked never iterates rows, so the question does not arise there.

Trait Implementations

impl<'a> Clone for ColumnScope<'a>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a> Copy for ColumnScope<'a>

impl<'a> Debug for ColumnScope<'a>

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

Formats the value using the given formatter.