Hi, I'm very interested helping you creating your 4 ER diagrams, I have years of experience in SQL and database administration, modeling, and manipulating, please do not hesitate to check my portfolio, there is some samples of databases modeling and database administration manual. I've checked your requirement I can do this job in the deadline without a problem, because I've done many projects like this (I've attached an example of ERD in my portfolio section). Please send me all other details about your ERD, so we can start asap. I'm available, and can start immediately. Looking forward to working with you. Thank you for your consideration. Regards