$1.$ Create database diagram and check it corectness $($compare with a diagram above$).2.$ Add data from the script $($library$\_$eng$\_$data.sql$).$ In case of errors, check the defined structure again.. $3.$ There is Gender field in Employees table omitted $($it should contain $\text{'}$F$\text{'}$ or $"$M$\text{'}$ value$).$ Correct this mistake. $4.$ Change Book$\_$loans tabel $-$ add another constraint, that enforces uniqueness of a pair of values : BookID and DateOut.