entity query and record progress

backends/mysql/include/mysql_connection.hpp

@@ -37,7 +37,7 @@ public:
 
   size_t execute(const std::string &stmt) override;
 
-  sql::record describe(const std::string& table) override;
+  std::vector<sql::column_definition> describe(const std::string& table) override;
 
   bool exists(const std::string &schema_name, const std::string &table_name) override;