These accounts have attributes like account number, account opening date, account expiry date, principal amount, maturity amount, account balance, interest rate, checks issued, pre-cancellation fee etc. Here employee will be the superset for the entities HR Employee and IT employee, but again it is a subtype for the PEOPLE entity.Ī person can open a savings account or a certificate deposit (fixed deposit) in a bank. Based on this scenario, employee entity can be further classified under different subtype entities like HR employee, IT employee etc. People entity will have attributes like Name, Address, and Telephone number, which are common to its subtypes and you can design entities employee, vendor, and consumer with their own unique attributes. When designing a data model for PEOPLE, you can have a supertype entity of PEOPLE and its subtype entities can be vendor, customer, and employee. People, Bank Account, Insurance, Asset, Liability, Credit Card. ![]() Supertypes and Subtypes are parent and child entities respectively and the primary keys of supertype and subtype are always identical.Į.g. Subtypes are subgroups of the supertype entity and have unique attributes, but they will be different from each subtype. Supertype is an entity type that has got relationship (parent to child relationship) with one or more subtypes and it contains attributes that are common to its subtypes. ![]() Based on the attributes, these entities are categorized as Supertype and Subtype entities. ![]() At times, few entities in a data model may share some common properties (attributes) within themselves apart from having one or more distinct attributes.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |