fixed backend tests

include/matador/query/query_compiler.hpp

@@ -6,6 +6,8 @@
 
 #include "matador/sql/query_context.hpp"
 
+#include "matador/utils/placeholder.hpp"
+
 namespace matador::sql {
 class connection_impl;
 class dialect;
@@ -14,6 +16,7 @@ class dialect;
 namespace matador::query {
 
 struct query_data;
+struct value_visitor;
 
 class query_compiler final : public query_part_visitor
 {
@@ -52,6 +55,8 @@ protected:
 
   static std::string build_table_name(sql::dialect_token token, const sql::dialect &d, const sql::table& t);
 
+  std::string determine_value(value_visitor &visitor, const std::variant<utils::placeholder, utils::database_type> &val);
+
 protected:
   const query_data *data_{};
   sql::query_context query_;

include/matador/query/query_data.hpp

@@ -5,17 +5,25 @@
 #include <vector>
 
 #include "matador/object/attribute_definition.hpp"
+
 #include "matador/sql/table.hpp"
 
 #include "matador/query/query_part.hpp"
 
 namespace matador::query {
-struct query_data
-{
-  std::vector<std::unique_ptr<query_part>> parts{};
-  std::vector<object::attribute_definition> columns{};
-  std::unordered_map<std::string, sql::table> tables{};
+
+enum struct query_mode {
+    Direct = 0,
+    Prepared = 1
 };
+
+struct query_data {
+    std::vector<std::unique_ptr<query_part>> parts{};
+    std::vector<object::attribute_definition> columns{};
+    std::unordered_map<std::string, sql::table> tables{};
+    query_mode mode = query_mode::Direct;
+};
+
 }
 
 #endif //QUERY_DATA_HPP