private void CreateFolder() throws SQLException{
    	boolean isExist = false;

    	if(Objects.equals(currProjectName,"") || selected == null){
            warning("Can't create folder under the main project");
    	} else if(selected.getValue().isProject()){
    		TextInputDialog dialog = new TextInputDialog("");
        	dialog.setTitle("Create Folder");
        	dialog.setHeaderText("Folder");
        	dialog.setContentText("Please enter the folder name:");
        	Optional<String> result = dialog.showAndWait();

        	if (result.isPresent()){
        		final String inputFolderName  = result.get();

        		String query = "SELECT pdname FROM PDirs where pid like '" + currPID + "' AND parentid IS NULL";
        		Statement st = conn.createStatement();
        		ResultSet rs = st.executeQuery(query);

                    while(rs.next()){
                    	String tempName = rs.getString("pdname");
                    	if(Objects.equals(tempName,inputFolderName)){
                    		isExist = true;
                    		break;
                    	}
                    }
        		if(isExist == true){
        			warning("Directory name already exist.");

        		} else {
        			query = "INSERT INTO PDirs(pdname, pid) VALUE('" + inputFolderName + "','" + currPID + "')";
        			st = conn.createStatement();
        			st.executeUpdate(query);
        			query = "SELECT LAST_INSERT_ID()";
        			rs = st.executeQuery(query);
        			if(rs.next()){
        				int currID = rs.getInt("LAST_INSERT_ID()");
        				CheckBoxTreeItem<StrucTree> temptreeItem = new CheckBoxTreeItem<>();
        				temptreeItem.setValue(new StrucTree("d", inputFolderName, currID));
        				selected.getChildren().add(temptreeItem);
        				selected.setExpanded(true);
        			}
        		}
        	}
    } else if(selected.getValue().isFile()){
		TextInputDialog dialog = new TextInputDialog("");
    	dialog.setTitle("Create Folder");
    	dialog.setHeaderText("Folder");
    	dialog.setContentText("Please enter the folder name:");
    	Optional<String> result = dialog.showAndWait();

    	if (result.isPresent()){
    		final String inputFolderName  = result.get();
    		String query = "";
    		if(selected.getParent().getValue().isProject()){
    			query = "SELECT pdname FROM PDirs where pid like '" + currPID + "' AND parentid IS NULL";
    		}else {
    			query = "SELECT pdname FROM PDirs where pid like '" + currPID + "' AND parentid like '" + selected.getParent().getValue().getID() + "'";
    		}
    		Statement st = conn.createStatement();
    		ResultSet rs = st.executeQuery(query);

                while(rs.next()){
                	String tempName = rs.getString("pdname");
                	if(Objects.equals(tempName,inputFolderName)){
                		isExist = true;
                		break;
                	}
                }
                if(isExist == true){
        			warning("Directory name already exist.");
        		} else {
        	   		if(selected.getParent().getValue().isProject()){
            			query = "INSERT INTO PDirs(pdname, pid) VALUE('" + inputFolderName + "','" + currPID + "')";
            		}else {
            			query = "INSERT INTO PDirs(pdname, pid,parentid) VALUE('" + inputFolderName + "','" + currPID + "','" + selected.getParent().getValue().getID() + "')";
            		}
        			st = conn.createStatement();
        			st.executeUpdate(query);
        			query = "SELECT LAST_INSERT_ID()";
        			rs = st.executeQuery(query);
        			if(rs.next()){
        				int currID = rs.getInt("LAST_INSERT_ID()");
        				CheckBoxTreeItem<StrucTree> temptreeItem = new CheckBoxTreeItem<>();
            	   		if(selected.getParent().getValue().isProject()){
            	   			temptreeItem.setValue(new StrucTree("d", inputFolderName, currID));
            	   		}else {
            	   			temptreeItem.setValue(new StrucTree("d", inputFolderName, currID, selected.getParent().getValue().getID()));
            	   		}
        				selected.getParent().getChildren().add(temptreeItem);
        				selected.getParent().setExpanded(true);
        			}
        		}
    	}
    } else if(selected.getValue().isDirectory()){
		TextInputDialog dialog = new TextInputDialog("");
    	dialog.setTitle("Create Folder");
    	dialog.setHeaderText("Folder");
    	dialog.setContentText("Please enter the folder name:");
    	Optional<String> result = dialog.showAndWait();

    	if (result.isPresent()){
    		final String inputFolderName  = result.get();
    		String query = "SELECT pdname FROM PDirs where pid like '" + currPID + "' AND parentid like '" + selected.getValue().getID() + "'";
    		Statement st = conn.createStatement();
    		ResultSet rs = st.executeQuery(query);

                while(rs.next()){
                	String tempName = rs.getString("pdname");
                	if(Objects.equals(tempName,inputFolderName)){
                		isExist = true;
                		break;
                	}
                }
    		if(isExist == true){
    			warning("Directory name already exist.");
    		} else {
    			query = "INSERT INTO PDirs(pdname, pid, parentid) VALUE('" + inputFolderName + "','" + currPID + "','" + selected.getValue().getID() + "')";
    			st = conn.createStatement();
    			st.executeUpdate(query);
    			query = "SELECT LAST_INSERT_ID()";
    			rs = st.executeQuery(query);
    			if(rs.next()){
    				int currID = rs.getInt("LAST_INSERT_ID()");
    				CheckBoxTreeItem<StrucTree> temptreeItem = new CheckBoxTreeItem<>();
    				temptreeItem.setValue(new StrucTree("d", inputFolderName, currID, selected.getValue().getID()));
    				selected.getChildren().add(temptreeItem);
    				selected.setExpanded(true);
    			}
    		}
    	}

    }


    }