Database-Management-System
August 29, 2024Database-Management-System
August 29, 2024Database-Management-System
| Question 376 |
A tuple relational calculus query is expressed as ___
| {T | p(T)}
| |
| { P() | T }
| |
| { p() | T}
| |
| {T | P() | T} |
Question 376 Explanation:
The tuple relational calculus is based on specifying a number of tuple variables. Each tuple variable usually ranges over a particular database relation, meaning that the variable may take as its value any individual tuple from that relation. A simple tuple relational calculus query is of the form:
{t | P(t)}
where t is a tuple variable and P(t) is a conditional (Boolean) expression involving t that evaluates to either TRUE or FALSE for different assignments of tuples to the variable t. The result of such a query is the set of all tuples that evaluate P(t) to TRUE. These tuples are said to satisfy P(t).
{t | P(t)}
where t is a tuple variable and P(t) is a conditional (Boolean) expression involving t that evaluates to either TRUE or FALSE for different assignments of tuples to the variable t. The result of such a query is the set of all tuples that evaluate P(t) to TRUE. These tuples are said to satisfy P(t).
Correct Answer: A
Question 376 Explanation:
The tuple relational calculus is based on specifying a number of tuple variables. Each tuple variable usually ranges over a particular database relation, meaning that the variable may take as its value any individual tuple from that relation. A simple tuple relational calculus query is of the form:
{t | P(t)}
where t is a tuple variable and P(t) is a conditional (Boolean) expression involving t that evaluates to either TRUE or FALSE for different assignments of tuples to the variable t. The result of such a query is the set of all tuples that evaluate P(t) to TRUE. These tuples are said to satisfy P(t).
{t | P(t)}
where t is a tuple variable and P(t) is a conditional (Boolean) expression involving t that evaluates to either TRUE or FALSE for different assignments of tuples to the variable t. The result of such a query is the set of all tuples that evaluate P(t) to TRUE. These tuples are said to satisfy P(t).