Draw an ER diagram

Design a relational database for a government agency OSHPD. The agency reviews and approves various biology related projects submitted by researchers from several universities and other health related agencies. These researchers are identified as investigators by the agency. Each project can be done by either one investigator or more. If it is just one investigator then he/she is called as Primary Investigator (PI). If the project has more than one investigator, then there will be one PI and all the others are Co-PIs. The agency has all the details of an investigator: first name, last name, organization, address, and phone number. An investigator can be identified by his SSN as there may be two investigators with same first name and last name. One investigator can be PI for one project and Co-PI for another project. Each investigator may have several projects with the agency. Each project may be written in various languages like English, Hindi, French, Spanish and Korean, although mostly English is used. Each project is reviewed by more than one reviewer. The reviewer is also identified by his SSN as there may be two reviewers with the same first name and last name. For a given project, a reviewers role can be primary, secondary or optional. Each project has a title, status, and whether it is archived or not. Each project is identified by its project ID. A contact history is maintained for each project. A contact person (PI or Co-PI or anybody from PIs office) can contact the agency employees regarding the project. The contact history details that the agency maintains are contact person name, contact details, contact type, and contact reminders. Contact type is the type of contact made for the project that is either phone or email. Contact details are the details of the conversation of the contact person with the agency employee either on phone or via email. The contact remainders are remainders that are sent or received after a contact is made.

Constraints:

Each project should have at least one investigator.

Each investigator will have at least one project.

An investigator can do any number of projects.

The investigators role can be primary (PI) or secondary (Co-PI).

Each reviewer should review at least one project.

A project must be reviewed by at least 2 reviewers.

A reviewer can review many projects, but should review at least one project.

The contact history is dependent on the project as each projects contact history is recorded. The contact id is just for that particular project.

A project can have many contact histories where as a contact history is just related to one project.