Draw an ERD based on the following scenario

- A laboratory has several chemists who work on one or more projects. Chemists also may use certain kinds of equipment on each project.

- A chemist must be assigned to at least one project but need not be assigned to an equipment item. The same chemist could be assigned to the same project more than once if more than one equipment item is needed for a given project.

- A given equipment item may be assigned to multiple projects and chemists. However, a given equipment item need not be assigned to either a chemist or a project.

- A given project need not be assigned to either a chemist or an equipment item. However, the same project could be assigned to multiple chemists and equipment items.

- The organization wishes to record assignDate, which is the date when a given equipment item was assigned to a particular chemist working on a specified project.

- Each manufacturer sells several equipment items. An equipment item could be sold by several different manufacturers and the price will vary from one manufacturer to another

- Every project requires one project manager which is a chemist. Not all chemist manage projects but some chemists manage more than one project.

- Chemists require that another chemist be designated as their emergency contact. Some chemists serve as an emergency contact for several other chemists. However, not all chemists server as an emergency contact for other chemists.

NOTES:

- If additional assumptions are required make sure to clearly indicate them on your diagram

- Make sure you use proper ERD notation for attributes, entity types and relationships (use verbs for all non-associative relationships)

- Show cardinalities, primary keys and foreign keys

- Resolve all multi-valued attributes & M:N relationships properly