author publisher патe name address address URL phone URL customer email written_by патe published_by address phone book | питber ISBN title shopping_basket basket_of Jear contains basket_id price пиmber warehouse code stocks address phone Figure 6.30 E-R diagram for modeling an online bookstore.

Create an ER diagram for a reservation system of hotel rooms considering the following facts. You should indicate some attributes and the primary key for each entity. ■ Hotel contains several rooms Customer can reserve one or more rooms One room contains one, two, or three beds ⚫ Bed can be normal (for one person), double, or spare (less expensive)

Draw a UML state diagram for the states of the application. The diagram must show the guards.

An E-R diagram can be viewed as a graph. What do the following mean in termsof the structure of an enterprise schema?. The graph has a cycle.