small fixes for table, column and query_macro

source/orm/query/builder.cpp

@@ -18,7 +18,7 @@ table_builder& table_builder::as( std::string table_alias ) {
 }
 
 table_builder::operator class query::table() const {
-  return {table_name, alias};
+  return {table_name, alias, {}};
 }
 
 constraint_builder& constraint_builder::constraint( std::string name ) {

source/orm/query/column.cpp

@@ -98,4 +98,9 @@ std::shared_ptr<table> column::table() const {
 void column::table( const std::shared_ptr<query::table>& t ) {
   table_ = t;
 }
+
+column::operator const std::string&() const {
+  return name;
+}
+
 }

source/orm/query/table.cpp

@@ -10,17 +10,12 @@ table::table(std::string name)
 : name_(std::move(name))
 {}
 
-table::table(const char *name, std::string as)
-: name_(name)
-, alias_(std::move(as))
-{}
-
 table::table(std::string name, std::string as)
 : name_(std::move(name))
 , alias_(std::move(as))
 {}
 
-table::table( std::string name, std::string as, const std::vector<column>& columns )
+table::table( std::string name, std::string as, const std::vector<query::column>& columns )
 : name_(std::move(name))
 , alias_(std::move(as))
 , columns_(columns) {}
@@ -54,7 +49,11 @@ const std::vector<column>& table::columns() const {
   return columns_;
 }
 
-table::operator const std::vector<column>&() const {
+column table::column( const std::string& name ) const {
+  return {*this, name};
+}
+
+table::operator const std::vector<query::column>&() const {
   return columns_;
 }