An identifying relationship means that the child table cannot be uniquely identified without the parent. For example, you have this situation in the intersection table used to resolve a many-to-many relationship where the intersecting table's Primary Key is a composite of the left and right (parents) table's Primary Keys.
标识关系中，子表种的记录不能脱离父表独立存在。
Example...
Account (AccountID, AccountNum, AccountTypeID)
PersonAccount (AccountID, PersonID, Balance)
Person(PersonID, Name)
The Account to PersonAccount relationship and the Person to PersonAccount relationship are identifying because the child row (PersonAccount) cannot exist without having been defined in the parent (Account or Person). In other words: there is no personaccount when there is no Person or when there is no Account.
Account实体和PersonAccount实体，以及Person实体和PersonAccount实体之间就是标识关系，因为如果父表中没有相应记录，子表（PersonAccount）中相应记录就不可以存在。简而言之，不可能存在没有Person或者没有Account的PersonAccount记录。通俗一点就是，没有父亲就不会有他的孩子。
A non-identifying relationship is one where the child can be identified independently of the parent ( Account - AccountType)
非标识关系中，子表中的记录可以独立存在，而不依赖于父表。
Example...
Account( AccountID, AccountNum, AccountTypeID )
AccountType( AccountTypeID, Code, Name, Description )
The relationship between Account and AccountType is non-identifying because each AccountType can be identified without having to exist in the parent table.
You can define the relationship type (identifying/non identifying) in the DeZign for Databases in the relationship dialog. Double click on the relationship line in the diagram window to display the relationship dialog.
上例中，Account和AccountType就是非标识关系，即使没有Account记录，也可以有AccountType记录，通俗一点就是，没有你照样有男人和女人。
转载自原文链接, 如需删除请联系管理员。
原文链接：Identifying and Non-Identifying Relationships （标识和非标识关系），转载请注明来源！