private Column createColumn(String type, String name) {
    	Column c = null;
    	type = type.toLowerCase();
    	if (type.equals("categorical")) { 
    		c = new StringColumn(name);
    	}
    	else if (type.equals("string")) {
    		c = new StringColumn(name);
    	}
    	else if (type.equals("integer")) {
    		c = new IntColumn(name);
    	}
    	else if (type.equals("float")) {
    		c = new RealColumn(name);
    	}
    	return c;
    }