When creating a student roster, a school cannot enroll more than $20$ students per course. This is an example of what data modeling building block? a$.$ attribute b$.$ entity c$.$ relationship d$.$ constraint $27.$ In a relational table, an intersection of a row and a column represents $\_\_\_\_\_\_\_\_\_\_\_\_.$ a$.$ an entity b$.$ a vertical subset c$.$ a single data value d$.$ an attribute $28.\_\_\_\_\_$ logic, used extensively in mathematics, provides a framework in which an assertion $($statement of fact$)$ can be verified as either true or false. a$.$ Predicate b$.$ Database c$.$ Relational d$.$ Index $29.$ Character data, also known as $\_\_\_$ data, can contain any character or symbol not intended for mathematical manipulation. a$.$ unsigned integer b$.$ signed integer c$.$ string d$.$ content $30.$ Relations are a $\_\_\_\_\_\_\_\_$ construct, thus it's easier for users to think in terms of tables. a$.$ metaphysical b$.$ mathematical c$.$ hardware d$.$ physical