Thomas Edison was a key inventor in terms of audio recording.

What triggered the move toward magazine specialization in the 20th century?

Which of these could conceivably be entity types on an ER diagram? Select all options that apply. No partial credit.

Given the following ERD, select the option that is consistent with it.

        Given the ERD above, select all options that are acceptable ways of adding an associative entity type. Please be careful.  Please be careful when you select your options. The check box for each answer choice appears to the left and ABOVE the corresponding image.

The diagram below captures the situation where each employee can work on zero or several projects, and each project can have zero or many employees working for it. On the left are several attributes. Match each of them to appropriate entity type on the right. More than one attribute can map to a given entity type. Some items on the right might remain unmatched. 

Based on the ER diagram below, select the choice that correctly depicts the primary keys for the two entity types.

Each of the following five answer choices mentions 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 us assume that we draw five 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.

In a certain company each region could have several salespersons or none. Each salesperson is assigned to one or several regions. Which of the following ER diagrams best represents this scenario? At this stage, ignore the need for associative entity types. Please be careful when you select your option. The radio button for the answer choice appears to the left and ABOVE the corresponding image.

Given the ERD below, select the correct option for the number of attributes (including primary and foreign keys) for the two entity types on the diagram.