added mysql backend

backends/mysql/src/mysql_error.cpp

@@ -0,0 +1,30 @@
+#include "mysql_error.hpp"
+
+#include <sstream>
+
+namespace matador::backends::mysql {
+
+void throw_mysql_error(const char *what, const std::string &source)
+{
+  std::stringstream msg;
+  msg << "mysql error (" << source << "): " << what;
+  throw std::logic_error(msg.str());
+}
+
+void throw_mysql_error(MYSQL *db, const std::string &source)
+{
+  if (mysql_errno(db) != 0) {
+    throw_mysql_error(mysql_error(db), source);
+  }
+}
+
+void throw_mysql_error(MYSQL_STMT *stmt, const std::string &source, const std::string &sql)
+{
+  if (mysql_stmt_errno(stmt) != 0) {
+    std::stringstream msg;
+    msg << "mysql error (" << source << ") " << mysql_stmt_error(stmt) << ": " << sql;
+    throw std::logic_error(msg.str());
+  }
+}
+
+}