In the ideal gas law equation, what does the variable n stands for B. moles of gas. (n: a lowercase ânâ stands for the number of moles of a gas. [ This is a measurement in moles, so if you are given a mass in grams or kilograms, be sure to change it to moles first.) ]. Expert answered| cecillereign |Points 261|.
Theta-Join I The theta-join of two relations R and S is the set of tuples in theCartesian product of R and S that satisfy some condition C.RA R ./ C SSQL SELECT *FROM R, SWHERE C; I R ./ C S = Ë C (R S): T. M. Murali August 30, 2010 CS4604: SQL and Relational Algebra. Results of operations are also sets of tuples. (Later, we will dene arelational algebra on bags.) I Think of expressions in relational algebra as queries, which construct newrelations from given relations. I Four types of operators: I Remove parts of a single relation: projection and selection.
The relational algebra uses set union, set difference, and Cartesian product from set theory, but adds additional constraints to these operators.For set union and set difference, the two relations involved must be union-compatible âthat is, the two relations must have the same set of attributes.hereas the result of a join (or inner join) consists of tuples formed by combining matching tuples in the two operands, an outer join contains those tuples and additionally some tuples formed by extending an unmatched tuple in one of the operands by fill values for each of the attributes of the other operand.