 ﻗﻴﻮﺩ ﺍﻧﻮﺍﻉ ﺍﻟﻌﻼﻗﺎﺕ ) ( Relationship types Constraints • ﻣﻦ ﺍﻟﻌﺎﻟﻢ ﺍﻟﺤﻘﻴﻘﻲ ﻧﺠﺪ