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Expert-verified Found in: Page 590 ### Discrete Mathematics and its Applications

Book edition 7th
Author(s) Kenneth H. Rosen
Pages 808 pages
ISBN 9780073383095 # What do you obtain when you apply the selection operator $${s_C}$$, where $$C$$ is the condition (Project $$= 2$$ ) $$\wedge$$ (Quantity $$\ge 50$$ ), to the database in Table 10 ? The resultant answer is (9191, 2, 80, 4).

See the step by step solution

## Step 1: Given data

Table 10 is given.

## Step 2: Concept of sets

The concept of set is a very basic one. It is simple; yet, it suffices as the basis on which all abstract notions in mathematics can be built. $$A$$ set is determined by its elements. If $$A$$ is a set, write $$x \in A$$ to say that $$x$$ is an element of $$A$$.

## Step 3: Simplify the expression

The application of the selection operator $${s_C}$$ results in all possible $$n$$-tuples in the database that satisfy the condition $$C$$.

$$C$$ is the condition $$({\rm{ Project }} = 2) \wedge ({\rm{ Quantity }} \ge 50)$$.

The application of the selection operator results in this case in all $$n$$-tuples that contains project 2 and a quantity of at least 50.

In table 10, note that the only part with a quantity of at least 50 is given in the bottom row of the table.

Note that this row has project 2. The corresponding $$n$$-tuple is: $$(9191,2,80,4)$$ ### Want to see more solutions like these? 