The Rel Forum

Posted: **Tue Oct 26, 2010 7:39 pm**

Hi, I created a relvar with a relation-valued attribute an I inserted some tuples. can you tell me how to query relation-valued values?
Thanks

Posted: **Wed Oct 27, 2010 11:15 pm**

Given, for example, this:

Code: Select all

VAR aVar REAL RELATION {x INTEGER, y RELATION {a INTEGER, b INTEGER}} KEY {x};

INSERT aVar RELATION {
  TUPLE {x 1, y RELATION {TUPLE {a 45, b 13}, TUPLE {a 33, b 4}}},
  TUPLE {x 2, y RELATION {TUPLE {a 7, b 28}}},
  TUPLE {x 3, y RELATION {TUPLE {a 3, b -3}, TUPLE {a 34, b 12}, TUPLE {a -3, b 45}}}
};

You can do queries like this:

Code: Select all

aVar WHERE x > 1 AND TUPLE {a 3, b -3} IN y

Or this:

Code: Select all

aVar WHERE x > 1 AND SUM(y, a) > 2

Etc.

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