QL for QL: make node column unique

Author: nickrolfe

ql/generator/src/main.rs

@@ -259,7 +259,7 @@ fn create_ast_node_info_table<'a>(
             dbscheme::Column {
                 db_type: dbscheme::DbColumnType::Int,
                 name: "node",
-                unique: false,
+                unique: true,
                 ql_type: ql::Type::At(ast_node_name),
                 ql_type_is_ref: true,
             },

ql/ql/src/ql.dbscheme

@@ -1063,7 +1063,7 @@ case @ql_token.kind of
 
 #keyset[parent, parent_index]
 ql_ast_node_info(
-  int node: @ql_ast_node ref,
+  unique int node: @ql_ast_node ref,
   int parent: @ql_ast_node_parent ref,
   int parent_index: int ref,
   int loc: @location ref