Consider a database containing information about art for sale, and local art galleries. Create entities and relationships as appropriate for each situation.

Information that is true for all of the following ER diagrams: Each and every art item has a unique identifying number, and also a name and asking price.

For each of the following situations, draw an ER diagram that describes it. Consider each situation independently. (Multiple situations means multiple, separate ER diagrams in a correct homework solution.)

1)

a. Art galleries have identifying business licence numbers, names, addresses and phone numbers. Art items can be displayed in art galleries. Some art items are not on display anywhere, some art items are displayed in multiple art galleries. Every art gallery must have at least one art item on display.

b. Artists have artist identifiers, last names, first name, and Facebook pages. Each art item is made by exactly one artist, however, each artist may have created many art items or none.

c. Art galleries participate in multiple art fairs. Each time a gallery participates in an art fair, the database stores the date, the name of the art fair date the gallery participated, the name of the art fair, a count of how many items the gallery brought to the fair, and a count of how many items sold. For each art gallery, the date and name of of the art fair, together, identify a trip an art fair. However, art fairs involve many vendors selling art, so a date and fair name pairing cannot identify a fair visit unless the gallery identifier is included.

d. Some art items are two-dimensional, some art items are three-dimensional. For two-dimensional art, the database stores height, width, and a recommendation about how to hang the art. (The recommendation is a string.) For three-dimensional art, the database stores the weight and whether the item is safe for outside display or not. Art is either two-dimensional or three-, not ever both. Some art items are simply art items, with no two- or three- dimensional data.

e. Some art items are included in books about art. An art book is identified with an ISBN, and the database also stores the title, author and year of publication. A book about art must include information about at least one art item, however, some art is not in any book. When an art item is included in a book, the database includes information about how it is included -- photo, discussion, sketch, etc. This information is about how the art is included in the book, not about either the art item or the book itself.