message: TransformationTypeCast for BLOB values: change T_PGString to T_PGBitString.
diff: @@ -14,8 +14,21 @@ unique_ptr<ParsedExpression> Transformer::TransformTypeCast(PGTypeCast *root) {
  auto type_name = root->typeName;
  SQLType target_type = TransformTypeName(type_name);
  + //check by a constant BLOB value, then change PGAConstant value type to T_PGBitString
  + if(target_type == SQLType::BLOB && root->arg->type == T_PGAConst) {
  + PGAConst *c = reinterpret_cast<PGAConst *>(root->arg);
  + c->val.type = T_PGBitString;
  + }
  +
  // transform the expression node
  auto expression = TransformExpression(root->arg);
  +
  +// //check by a constant VARCHAR value
  +// if(expression->type == ExpressionType::VALUE_CONSTANT && target_type == SQLType::VARCHAR) {
  +// auto constant_expression_ptr = static_cast<ConstantExpression*>(expression.get());
  +// //validating VARCHAR and scape BLOB strings
  +// constant_expression_ptr->value.ValidateString();
  +// }
  // now create a cast operation
  return make_unique<CastExpression>(target_type, move(expression));
  }
  