The diagram below captures the situation where each home could engage several contractors for work (like plumbing, roofing, electrical, etc) and each contractor could be working on several homes. On the left are several attributes. Match each of them to appropriate entity types on the right. More than one attribute can map to a given entity type, and therefore some items on the right might remain unmatched.

Each of the following four descriptions mentiones two entity types. Let us refer to the first entity type mentioned in each description as A, and the second entity type mentioned as B. For example, if the description stated ” We have several customers (A), and store an id, name and address for each customer. We have several cars (B), and store an id, vin_no, make and model for each. Each car can belong to at most one customer and each customer can have zero or many cars.” In this example, we mentioned Customers first and hence that entity type would be referred to as A and Cars would be referred to as B. Let ua assume that we draw four separate entity relationship diagrams, one for each description. Which of the descriptions will result in a foreign key occurring in entity type A? You have to select all the correct answers. No partial credit. You will get credit only if you choose all the correct choices and none of the incorrect ones.

Select the diagram that best captures the description below: Each vendor might be the supplier of several materials or none. Each material might be supplied by several vendors or none.  

Given the diagram below, we would like to place a relationship name for the entity type on the left. Which of the options is consistent with our convention for naming relationships?

In a certain office, every person is assigned an office. Every office is assigned to one person or could be empty. Select the diagram below that matches this description. Choose only one

How many optional attributes does the following entity type have?

Which of the following could conceivably be entity types on an ER diagram? Select all that apply. 

From the diagram below, indicate how many Cities does a Conductor correspond to. You can infer this even though there is no direct relationship between these entity types.

Based on the following diagram, what is the number of optional attributes in the two entity types? Consider the implicit and explicit ones.

For word recognition, what should be used as a last resort?