Struct NamePreserver

pub struct NamePreserver { /* private fields */ }

Re-export of NamesPreserver for backwards compatibility, as it was initially placed here and then moved elsewhere. Handles ensuring the name of rewritten expressions is not changed.

This is important when optimizing plans to ensure the output schema of plan nodes don’t change after optimization. For example, if an expression 1 + 2 is rewritten to 3, the name of the expression should be preserved: 3 as "1 + 2"

See https://github.com/apache/datafusion/issues/3555 for details

Implementations

impl NamePreserver

pub fn new(plan: &LogicalPlan) -> NamePreserver

Create a new NamePreserver for rewriting the expr that is part of the specified plan

pub fn new_for_projection() -> NamePreserver

Create a new NamePreserver for rewriting the exprs in Projection

This will use aliases

pub fn save(&self, expr: &Expr) -> SavedName