Design question

Hi,
I have an application that deals with an entity called "Document". A
"Document" can have several attributes. These attributes can be either
of {int, float, date, string} type. However, I do not know beforehand the number of attributes. The user may add more attributes to this
"Document" entity. For example, right now it may have attributes such
as <Author>, <Creation_Date>. Later, a user may add <Num_Pages>. So, modeling the "Document" entity as a relation with attributes as column names is difficult. I had this approach in mind and wanted to know if there is a better way.

I was thinking of creating a relation DocAttr(AttributeName, AttributeValue). I can create 4 such relations for each of {int, float, string and date}. DocAttrInt, DocAttrFloat, DocAttrString and DocAttrDate. Then I can store <Author, "Some Name"> in DocAttrString.

This way more attributes can be added on later or existing ones can be removed.

Is there a better way? Keep in mind that I am required to use an RDBMS. Thanks,
San Received on Sun May 04 2003 - 01:37:59 CDT