Re: Relational database comments

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muddu wrote:
> One of the properties of a relation or table is that every row is
> unique. If this is so,
> what do we do with a table of comments?
>
> Let's say, i want to put comments on a play in a relation. Two
> different people say
> "It was a great play". They both say exactly the same words. How
> can we put both comments
> in the relation if we must have uniqueness?
>

normalize!
You yourself said:
> Let's say, i want to put comments on a play in a relation. Two
> *different* people say
> "It was a great play". They both say exactly the same words. How
> can we put both comments
> in the relation if we must have uniqueness?

Two *different* people - there you have your uniqueness.

Now, whether to resolve this in a "who" and a "what comment" table (would yield less entries in the "what comment" table), or in a "who made what comment table" is up to you. That decision should be made, based on other requirements.

BTW, uniqueness in never "stored (put) in a relation"

Afterthought: what about an Alzheimer patient? - --
Regards,
Frank van Bortel

Top-posting is one way to shut me up...
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