Method add_column

src/repr/src/relation.rs:1709–1742

(&mut self, name: N, typ: T)

    /// Note: For building a [`RelationDesc`] see [`RelationDescBuilder::with_column`].
    #[must_use]
    pub fn add_column<N, T>(&mut self, name: N, typ: T) -> RelationVersion
    where
        N: Into<ColumnName>,
        T: Into<SqlColumnType>,
    {
        let latest_version = self.latest_version();
        let new_version = latest_version.bump();

        let name = name.into();
        let existing = self
            .inner
            .metadata
            .iter()
            .find(|(_, meta)| meta.name == name && meta.dropped.is_none());
        if let Some(existing) = existing {
            panic!("column named '{name}' already exists! {existing:?}");
        }

        let next_idx = self.inner.metadata.len();
        let col_meta = ColumnMetadata {
            name,
            typ_idx: next_idx,
            added: new_version,
            dropped: None,
        };

        self.inner.typ.column_types.push(typ.into());
        let prev = self.inner.metadata.insert(ColumnIndex(next_idx), col_meta);

        assert_none!(prev, "column index overlap!");
        self.validate();

        new_version
    }

    /// Drops the column `name` from this [`RelationDesc`]. If there are multiple columns with
    /// `name` drops the left-most one that hasn't already been dropped.