Question

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 ?

Short answer

The resultant answer is (9191, 2, 80, 4).

Step-by-step solution

Given data

Table 10 is given.

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\(A\).

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: \((9191,2,80,4)\)