Is it OK to assume that children are the dependents of one employee? That depends. What are the rules of your organization? What are you trying to track? Be careful if you decide it is OK. What happens if that assumption is wrong? Or changes over time? If you have doubts, be safe and do not assume that children are dependents of only one employee. As a general rule, when in doubt, assume a M:M relationship exists, or might in the future exist, between nouns.