Re: Extending my question. Was: The relational model and relational
Date: 24 Feb 2003 09:47:54 -0800
When you write a formula, say "i < j , where (i, j) in Integers)", you have not identified either i or j as being some particular integer. You have distinguished them and stated a property they have (i.e. ordering), as integers.
What you are arguing that I cannot write a formula which uses a representative element (a variable) from a set; that I can only write constants because constants have a unique identity and a variable does not.
>> That is the whole point! I have not counted them! ... Then you are
not even participating in the discussion. You are ignoring it instead and posting random meaningless gibberish -- as is your wont. <<
Will you please read a math book with a good introduction to set theory? You do not understand cardinality, how bound and free variables work or much about data modeling.
Multi-sets carry information, which is why Dr. Codd had to add a "Degree of Duplication" operator to his Relational Model. He realized that if duplicates do not exist, then everything would have a count of one. Received on Mon Feb 24 2003 - 18:47:54 CET