1) In a relational DBMS, a command violating any integrity constraint is always rejected.

True or False

2) A conceptual model of a database must reflect all relevant organizations business rules.

True or False

3) Provided relation R has three fields A, B, and C. I is an instance of R with N tuples. The expression _A(_{C >20}(I)) cannot return more than N tuples.

True or False

4) In the hierarchical data model, each segment participates in a parent-child relationship as a child.

True or False

5) In the relational data model, one of the fields of the composite primary key of a relation can accept Null value while the other ones are defined.

True or False