Function merge_create_table_hierarchy 

pub fn merge_create_table_hierarchy(
    context: &InheritanceContext<'_>,
    table: &mut CreateTable,
    notices: &mut Vec<SQLNotice>,
) -> Result<MergedParents, SQLError>

MergeAttributes: the columns, CHECK constraints and partition keys a new table inherits from its parents, ahead of its own, with the notices that report each merged column. DefineRelation first looks up every parent, rejecting one named twice; the table’s own columns cannot repeat a name. The table’s partition key and bound are bound by bind_create_table_partitioning once its row type is described, as DefineRelation computes them after creating the relation.