I typically design a system with primary keys defined, like this: CREATE TABLE employee ( employee_key integer DEFAULT nextval('employee_key_serial') PRIMARY KEY , I use scripts to build the database structures and load the data. I am careful to get the dependencies in the correct order, so that the keys later structures depend on already exist. Today I was going over the design for the current project with a friend, whose expertise i respect. he said that he had issues on a system designed by an OEM that had dependencies on keys developed from sequences after a backup/restore cycle, Will I potentially have these issues? If so, what can I do different to avoid this being an issue? -- "They that would give up essential liberty for temporary safety deserve neither liberty nor safety." -- Benjamin Franklin